(function (global, factory) {
    typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
        typeof define === 'function' && define.amd ? define(factory) :
            (global = typeof globalThis !== 'undefined' ? globalThis : global || self, global.VueRouter = factory());
}(this, (function () { 'use strict';

    /*  */

    function assert (condition, message) {
        if (!condition) {
            throw new Error(("[vue-router] " + message))
        }
    }

    function warn (condition, message) {
        if ( !condition) {
            typeof console !== 'undefined' && console.warn(("[vue-router] " + message));
        }
    }

    function extend (a, b) {
        for (var key in b) {
            a[key] = b[key];
        }
        return a
    }

    /*  */

    var encodeReserveRE = /[!'()*]/g;
    var encodeReserveReplacer = function (c) { return '%' + c.charCodeAt(0).toString(16); };
    var commaRE = /%2C/g;

    // fixed encodeURIComponent which is more conformant to RFC3986:
    // - escapes [!'()*]
    // - preserve commas
    var encode = function (str) { return encodeURIComponent(str)
        .replace(encodeReserveRE, encodeReserveReplacer)
        .replace(commaRE, ','); };

    function decode (str) {
        try {
            return decodeURIComponent(str)
        } catch (err) {
            {
                warn(false, ("Error decoding \"" + str + "\". Leaving it intact."));
            }
        }
        return str
    }

    function resolveQuery (
        query,
        extraQuery,
        _parseQuery
    ) {
        if ( extraQuery === void 0 ) extraQuery = {};

        var parse = _parseQuery || parseQuery;
        var parsedQuery;
        try {
            parsedQuery = parse(query || '');
        } catch (e) {
            warn(false, e.message);
            parsedQuery = {};
        }
        for (var key in extraQuery) {
            var value = extraQuery[key];
            parsedQuery[key] = Array.isArray(value)
                ? value.map(castQueryParamValue)
                : castQueryParamValue(value);
        }
        return parsedQuery
    }

    var castQueryParamValue = function (value) { return (value == null || typeof value === 'object' ? value : String(value)); };

    function parseQuery (query) {
        var res = {};

        query = query.trim().replace(/^(\?|#|&)/, '');

        if (!query) {
            return res
        }

        query.split('&').forEach(function (param) {
            var parts = param.replace(/\+/g, ' ').split('=');
            var key = decode(parts.shift());
            var val = parts.length > 0 ? decode(parts.join('=')) : null;

            if (res[key] === undefined) {
                res[key] = val;
            } else if (Array.isArray(res[key])) {
                res[key].push(val);
            } else {
                res[key] = [res[key], val];
            }
        });

        return res
    }

    function stringifyQuery (obj) {
        var res = obj
            ? Object.keys(obj)
                .map(function (key) {
                    var val = obj[key];

                    if (val === undefined) {
                        return ''
                    }

                    if (val === null) {
                        return encode(key)
                    }

                    if (Array.isArray(val)) {
                        var result = [];
                        val.forEach(function (val2) {
                            if (val2 === undefined) {
                                return
                            }
                            if (val2 === null) {
                                result.push(encode(key));
                            } else {
                                result.push(encode(key) + '=' + encode(val2));
                            }
                        });
                        return result.join('&')
                    }

                    return encode(key) + '=' + encode(val)
                })
                .filter(function (x) { return x.length > 0; })
                .join('&')
            : null;
        return res ? ("?" + res) : ''
    }

    /*  */

    var trailingSlashRE = /\/?$/;

    function createRoute (
        record,
        location,
        redirectedFrom,
        router
    ) {
        var stringifyQuery = router && router.options.stringifyQuery;

        var query = location.query || {};
        try {
            query = clone(query);
        } catch (e) {}

        var route = {
            name: location.name || (record && record.name),
            meta: (record && record.meta) || {},
            path: location.path || '/',
            hash: location.hash || '',
            query: query,
            params: location.params || {},
            fullPath: getFullPath(location, stringifyQuery),
            matched: record ? formatMatch(record) : []
        };
        if (redirectedFrom) {
            route.redirectedFrom = getFullPath(redirectedFrom, stringifyQuery);
        }
        return Object.freeze(route)
    }

    function clone (value) {
        if (Array.isArray(value)) {
            return value.map(clone)
        } else if (value && typeof value === 'object') {
            var res = {};
            for (var key in value) {
                res[key] = clone(value[key]);
            }
            return res
        } else {
            return value
        }
    }

    // the starting route that represents the initial state
    var START = createRoute(null, {
        path: '/'
    });

    function formatMatch (record) {
        var res = [];
        while (record) {
            res.unshift(record);
            record = record.parent;
        }
        return res
    }

    function getFullPath (
        ref,
        _stringifyQuery
    ) {
        var path = ref.path;
        var query = ref.query; if ( query === void 0 ) query = {};
        var hash = ref.hash; if ( hash === void 0 ) hash = '';

        var stringify = _stringifyQuery || stringifyQuery;
        return (path || '/') + stringify(query) + hash
    }

    function isSameRoute (a, b, onlyPath) {
        if (b === START) {
            return a === b
        } else if (!b) {
            return false
        } else if (a.path && b.path) {
            return a.path.replace(trailingSlashRE, '') === b.path.replace(trailingSlashRE, '') && (onlyPath ||
                a.hash === b.hash &&
                isObjectEqual(a.query, b.query))
        } else if (a.name && b.name) {
            return (
                a.name === b.name &&
                (onlyPath || (
                        a.hash === b.hash &&
                        isObjectEqual(a.query, b.query) &&
                        isObjectEqual(a.params, b.params))
                )
            )
        } else {
            return false
        }
    }

    function isObjectEqual (a, b) {
        if ( a === void 0 ) a = {};
        if ( b === void 0 ) b = {};

        // handle null value #1566
        if (!a || !b) { return a === b }
        var aKeys = Object.keys(a).sort();
        var bKeys = Object.keys(b).sort();
        if (aKeys.length !== bKeys.length) {
            return false
        }
        return aKeys.every(function (key, i) {
            var aVal = a[key];
            var bKey = bKeys[i];
            if (bKey !== key) { return false }
            var bVal = b[key];
            // query values can be null and undefined
            if (aVal == null || bVal == null) { return aVal === bVal }
            // check nested equality
            if (typeof aVal === 'object' && typeof bVal === 'object') {
                return isObjectEqual(aVal, bVal)
            }
            return String(aVal) === String(bVal)
        })
    }

    function isIncludedRoute (current, target) {
        return (
            current.path.replace(trailingSlashRE, '/').indexOf(
                target.path.replace(trailingSlashRE, '/')
            ) === 0 &&
            (!target.hash || current.hash === target.hash) &&
            queryIncludes(current.query, target.query)
        )
    }

    function queryIncludes (current, target) {
        for (var key in target) {
            if (!(key in current)) {
                return false
            }
        }
        return true
    }

    function handleRouteEntered (route) {
        for (var i = 0; i < route.matched.length; i++) {
            var record = route.matched[i];
            for (var name in record.instances) {
                var instance = record.instances[name];
                var cbs = record.enteredCbs[name];
                if (!instance || !cbs) { continue }
                delete record.enteredCbs[name];
                for (var i$1 = 0; i$1 < cbs.length; i$1++) {
                    if (!instance._isBeingDestroyed) { cbs[i$1](instance); }
                }
            }
        }
    }

    var View = {
        name: 'RouterView',
        functional: true,
        props: {
            name: {
                type: String,
                default: 'default'
            }
        },
        render: function render (_, ref) {
            var props = ref.props;
            var children = ref.children;
            var parent = ref.parent;
            var data = ref.data;

            // used by devtools to display a router-view badge
            data.routerView = true;

            // directly use parent context's createElement() function
            // so that components rendered by router-view can resolve named slots
            var h = parent.$createElement;
            var name = props.name;
            var route = parent.$route;
            var cache = parent._routerViewCache || (parent._routerViewCache = {});

            // determine current view depth, also check to see if the tree
            // has been toggled inactive but kept-alive.
            var depth = 0;
            var inactive = false;
            while (parent && parent._routerRoot !== parent) {
                var vnodeData = parent.$vnode ? parent.$vnode.data : {};
                if (vnodeData.routerView) {
                    depth++;
                }
                if (vnodeData.keepAlive && parent._directInactive && parent._inactive) {
                    inactive = true;
                }
                parent = parent.$parent;
            }
            data.routerViewDepth = depth;

            // render previous view if the tree is inactive and kept-alive
            if (inactive) {
                var cachedData = cache[name];
                var cachedComponent = cachedData && cachedData.component;
                if (cachedComponent) {
                    // #2301
                    // pass props
                    if (cachedData.configProps) {
                        fillPropsinData(cachedComponent, data, cachedData.route, cachedData.configProps);
                    }
                    return h(cachedComponent, data, children)
                } else {
                    // render previous empty view
                    return h()
                }
            }

            var matched = route.matched[depth];
            var component = matched && matched.components[name];

            // render empty node if no matched route or no config component
            if (!matched || !component) {
                cache[name] = null;
                return h()
            }

            // cache component
            cache[name] = { component: component };

            // attach instance registration hook
            // this will be called in the instance's injected lifecycle hooks
            data.registerRouteInstance = function (vm, val) {
                // val could be undefined for unregistration
                var current = matched.instances[name];
                if (
                    (val && current !== vm) ||
                    (!val && current === vm)
                ) {
                    matched.instances[name] = val;
                }
            }

            // also register instance in prepatch hook
            // in case the same component instance is reused across different routes
            ;(data.hook || (data.hook = {})).prepatch = function (_, vnode) {
                matched.instances[name] = vnode.componentInstance;
            };

            // register instance in init hook
            // in case kept-alive component be actived when routes changed
            data.hook.init = function (vnode) {
                if (vnode.data.keepAlive &&
                    vnode.componentInstance &&
                    vnode.componentInstance !== matched.instances[name]
                ) {
                    matched.instances[name] = vnode.componentInstance;
                }

                // if the route transition has already been confirmed then we weren't
                // able to call the cbs during confirmation as the component was not
                // registered yet, so we call it here.
                handleRouteEntered(route);
            };

            var configProps = matched.props && matched.props[name];
            // save route and configProps in cache
            if (configProps) {
                extend(cache[name], {
                    route: route,
                    configProps: configProps
                });
                fillPropsinData(component, data, route, configProps);
            }

            return h(component, data, children)
        }
    };

    function fillPropsinData (component, data, route, configProps) {
        // resolve props
        var propsToPass = data.props = resolveProps(route, configProps);
        if (propsToPass) {
            // clone to prevent mutation
            propsToPass = data.props = extend({}, propsToPass);
            // pass non-declared props as attrs
            var attrs = data.attrs = data.attrs || {};
            for (var key in propsToPass) {
                if (!component.props || !(key in component.props)) {
                    attrs[key] = propsToPass[key];
                    delete propsToPass[key];
                }
            }
        }
    }

    function resolveProps (route, config) {
        switch (typeof config) {
            case 'undefined':
                return
            case 'object':
                return config
            case 'function':
                return config(route)
            case 'boolean':
                return config ? route.params : undefined
            default:
            {
                warn(
                    false,
                    "props in \"" + (route.path) + "\" is a " + (typeof config) + ", " +
                    "expecting an object, function or boolean."
                );
            }
        }
    }

    /*  */

    function resolvePath (
        relative,
        base,
        append
    ) {
        var firstChar = relative.charAt(0);
        if (firstChar === '/') {
            return relative
        }

        if (firstChar === '?' || firstChar === '#') {
            return base + relative
        }

        var stack = base.split('/');

        // remove trailing segment if:
        // - not appending
        // - appending to trailing slash (last segment is empty)
        if (!append || !stack[stack.length - 1]) {
            stack.pop();
        }

        // resolve relative path
        var segments = relative.replace(/^\//, '').split('/');
        for (var i = 0; i < segments.length; i++) {
            var segment = segments[i];
            if (segment === '..') {
                stack.pop();
            } else if (segment !== '.') {
                stack.push(segment);
            }
        }

        // ensure leading slash
        if (stack[0] !== '') {
            stack.unshift('');
        }

        return stack.join('/')
    }

    function parsePath (path) {
        var hash = '';
        var query = '';

        var hashIndex = path.indexOf('#');
        if (hashIndex >= 0) {
            hash = path.slice(hashIndex);
            path = path.slice(0, hashIndex);
        }

        var queryIndex = path.indexOf('?');
        if (queryIndex >= 0) {
            query = path.slice(queryIndex + 1);
            path = path.slice(0, queryIndex);
        }

        return {
            path: path,
            query: query,
            hash: hash
        }
    }

    function cleanPath (path) {
        return path.replace(/\/\//g, '/')
    }

    var isarray = Array.isArray || function (arr) {
        return Object.prototype.toString.call(arr) == '[object Array]';
    };

    /**
     * Expose `pathToRegexp`.
     */
    var pathToRegexp_1 = pathToRegexp;
    var parse_1 = parse;
    var compile_1 = compile;
    var tokensToFunction_1 = tokensToFunction;
    var tokensToRegExp_1 = tokensToRegExp;

    /**
     * The main path matching regexp utility.
     *
     * @type {RegExp}
     */
    var PATH_REGEXP = new RegExp([
        // Match escaped characters that would otherwise appear in future matches.
        // This allows the user to escape special characters that won't transform.
        '(\\\\.)',
        // Match Express-style parameters and un-named parameters with a prefix
        // and optional suffixes. Matches appear as:
        //
        // "/:test(\\d+)?" => ["/", "test", "\d+", undefined, "?", undefined]
        // "/route(\\d+)"  => [undefined, undefined, undefined, "\d+", undefined, undefined]
        // "/*"            => ["/", undefined, undefined, undefined, undefined, "*"]
        '([\\/.])?(?:(?:\\:(\\w+)(?:\\(((?:\\\\.|[^\\\\()])+)\\))?|\\(((?:\\\\.|[^\\\\()])+)\\))([+*?])?|(\\*))'
    ].join('|'), 'g');

    /**
     * Parse a string for the raw tokens.
     *
     * @param  {string}  str
     * @param  {Object=} options
     * @return {!Array}
     */
    function parse (str, options) {
        var tokens = [];
        var key = 0;
        var index = 0;
        var path = '';
        var defaultDelimiter = options && options.delimiter || '/';
        var res;

        while ((res = PATH_REGEXP.exec(str)) != null) {
            var m = res[0];
            var escaped = res[1];
            var offset = res.index;
            path += str.slice(index, offset);
            index = offset + m.length;

            // Ignore already escaped sequences.
            if (escaped) {
                path += escaped[1];
                continue
            }

            var next = str[index];
            var prefix = res[2];
            var name = res[3];
            var capture = res[4];
            var group = res[5];
            var modifier = res[6];
            var asterisk = res[7];

            // Push the current path onto the tokens.
            if (path) {
                tokens.push(path);
                path = '';
            }

            var partial = prefix != null && next != null && next !== prefix;
            var repeat = modifier === '+' || modifier === '*';
            var optional = modifier === '?' || modifier === '*';
            var delimiter = res[2] || defaultDelimiter;
            var pattern = capture || group;

            tokens.push({
                name: name || key++,
                prefix: prefix || '',
                delimiter: delimiter,
                optional: optional,
                repeat: repeat,
                partial: partial,
                asterisk: !!asterisk,
                pattern: pattern ? escapeGroup(pattern) : (asterisk ? '.*' : '[^' + escapeString(delimiter) + ']+?')
            });
        }

        // Match any characters still remaining.
        if (index < str.length) {
            path += str.substr(index);
        }

        // If the path exists, push it onto the end.
        if (path) {
            tokens.push(path);
        }

        return tokens
    }

    /**
     * Compile a string to a template function for the path.
     *
     * @param  {string}             str
     * @param  {Object=}            options
     * @return {!function(Object=, Object=)}
     */
    function compile (str, options) {
        return tokensToFunction(parse(str, options), options)
    }

    /**
     * Prettier encoding of URI path segments.
     *
     * @param  {string}
     * @return {string}
     */
    function encodeURIComponentPretty (str) {
        return encodeURI(str).replace(/[\/?#]/g, function (c) {
            return '%' + c.charCodeAt(0).toString(16).toUpperCase()
        })
    }

    /**
     * Encode the asterisk parameter. Similar to `pretty`, but allows slashes.
     *
     * @param  {string}
     * @return {string}
     */
    function encodeAsterisk (str) {
        return encodeURI(str).replace(/[?#]/g, function (c) {
            return '%' + c.charCodeAt(0).toString(16).toUpperCase()
        })
    }

    /**
     * Expose a method for transforming tokens into the path function.
     */
    function tokensToFunction (tokens, options) {
        // Compile all the tokens into regexps.
        var matches = new Array(tokens.length);

        // Compile all the patterns before compilation.
        for (var i = 0; i < tokens.length; i++) {
            if (typeof tokens[i] === 'object') {
                matches[i] = new RegExp('^(?:' + tokens[i].pattern + ')$', flags(options));
            }
        }

        return function (obj, opts) {
            var path = '';
            var data = obj || {};
            var options = opts || {};
            var encode = options.pretty ? encodeURIComponentPretty : encodeURIComponent;

            for (var i = 0; i < tokens.length; i++) {
                var token = tokens[i];

                if (typeof token === 'string') {
                    path += token;

                    continue
                }

                var value = data[token.name];
                var segment;

                if (value == null) {
                    if (token.optional) {
                        // Prepend partial segment prefixes.
                        if (token.partial) {
                            path += token.prefix;
                        }

                        continue
                    } else {
                        throw new TypeError('Expected "' + token.name + '" to be defined')
                    }
                }

                if (isarray(value)) {
                    if (!token.repeat) {
                        throw new TypeError('Expected "' + token.name + '" to not repeat, but received `' + JSON.stringify(value) + '`')
                    }

                    if (value.length === 0) {
                        if (token.optional) {
                            continue
                        } else {
                            throw new TypeError('Expected "' + token.name + '" to not be empty')
                        }
                    }

                    for (var j = 0; j < value.length; j++) {
                        segment = encode(value[j]);

                        if (!matches[i].test(segment)) {
                            throw new TypeError('Expected all "' + token.name + '" to match "' + token.pattern + '", but received `' + JSON.stringify(segment) + '`')
                        }

                        path += (j === 0 ? token.prefix : token.delimiter) + segment;
                    }

                    continue
                }

                segment = token.asterisk ? encodeAsterisk(value) : encode(value);

                if (!matches[i].test(segment)) {
                    throw new TypeError('Expected "' + token.name + '" to match "' + token.pattern + '", but received "' + segment + '"')
                }

                path += token.prefix + segment;
            }

            return path
        }
    }

    /**
     * Escape a regular expression string.
     *
     * @param  {string} str
     * @return {string}
     */
    function escapeString (str) {
        return str.replace(/([.+*?=^!:${}()[\]|\/\\])/g, '\\$1')
    }

    /**
     * Escape the capturing group by escaping special characters and meaning.
     *
     * @param  {string} group
     * @return {string}
     */
    function escapeGroup (group) {
        return group.replace(/([=!:$\/()])/g, '\\$1')
    }

    /**
     * Attach the keys as a property of the regexp.
     *
     * @param  {!RegExp} re
     * @param  {Array}   keys
     * @return {!RegExp}
     */
    function attachKeys (re, keys) {
        re.keys = keys;
        return re
    }

    /**
     * Get the flags for a regexp from the options.
     *
     * @param  {Object} options
     * @return {string}
     */
    function flags (options) {
        return options && options.sensitive ? '' : 'i'
    }

    /**
     * Pull out keys from a regexp.
     *
     * @param  {!RegExp} path
     * @param  {!Array}  keys
     * @return {!RegExp}
     */
    function regexpToRegexp (path, keys) {
        // Use a negative lookahead to match only capturing groups.
        var groups = path.source.match(/\((?!\?)/g);

        if (groups) {
            for (var i = 0; i < groups.length; i++) {
                keys.push({
                    name: i,
                    prefix: null,
                    delimiter: null,
                    optional: false,
                    repeat: false,
                    partial: false,
                    asterisk: false,
                    pattern: null
                });
            }
        }

        return attachKeys(path, keys)
    }

    /**
     * Transform an array into a regexp.
     *
     * @param  {!Array}  path
     * @param  {Array}   keys
     * @param  {!Object} options
     * @return {!RegExp}
     */
    function arrayToRegexp (path, keys, options) {
        var parts = [];

        for (var i = 0; i < path.length; i++) {
            parts.push(pathToRegexp(path[i], keys, options).source);
        }

        var regexp = new RegExp('(?:' + parts.join('|') + ')', flags(options));

        return attachKeys(regexp, keys)
    }

    /**
     * Create a path regexp from string input.
     *
     * @param  {string}  path
     * @param  {!Array}  keys
     * @param  {!Object} options
     * @return {!RegExp}
     */
    function stringToRegexp (path, keys, options) {
        return tokensToRegExp(parse(path, options), keys, options)
    }

    /**
     * Expose a function for taking tokens and returning a RegExp.
     *
     * @param  {!Array}          tokens
     * @param  {(Array|Object)=} keys
     * @param  {Object=}         options
     * @return {!RegExp}
     */
    function tokensToRegExp (tokens, keys, options) {
        if (!isarray(keys)) {
            options = /** @type {!Object} */ (keys || options);
            keys = [];
        }

        options = options || {};

        var strict = options.strict;
        var end = options.end !== false;
        var route = '';

        // Iterate over the tokens and create our regexp string.
        for (var i = 0; i < tokens.length; i++) {
            var token = tokens[i];

            if (typeof token === 'string') {
                route += escapeString(token);
            } else {
                var prefix = escapeString(token.prefix);
                var capture = '(?:' + token.pattern + ')';

                keys.push(token);

                if (token.repeat) {
                    capture += '(?:' + prefix + capture + ')*';
                }

                if (token.optional) {
                    if (!token.partial) {
                        capture = '(?:' + prefix + '(' + capture + '))?';
                    } else {
                        capture = prefix + '(' + capture + ')?';
                    }
                } else {
                    capture = prefix + '(' + capture + ')';
                }

                route += capture;
            }
        }

        var delimiter = escapeString(options.delimiter || '/');
        var endsWithDelimiter = route.slice(-delimiter.length) === delimiter;

        // In non-strict mode we allow a slash at the end of match. If the path to
        // match already ends with a slash, we remove it for consistency. The slash
        // is valid at the end of a path match, not in the middle. This is important
        // in non-ending mode, where "/test/" shouldn't match "/test//route".
        if (!strict) {
            route = (endsWithDelimiter ? route.slice(0, -delimiter.length) : route) + '(?:' + delimiter + '(?=$))?';
        }

        if (end) {
            route += '$';
        } else {
            // In non-ending mode, we need the capturing groups to match as much as
            // possible by using a positive lookahead to the end or next path segment.
            route += strict && endsWithDelimiter ? '' : '(?=' + delimiter + '|$)';
        }

        return attachKeys(new RegExp('^' + route, flags(options)), keys)
    }

    /**
     * Normalize the given path string, returning a regular expression.
     *
     * An empty array can be passed in for the keys, which will hold the
     * placeholder key descriptions. For example, using `/user/:id`, `keys` will
     * contain `[{ name: 'id', delimiter: '/', optional: false, repeat: false }]`.
     *
     * @param  {(string|RegExp|Array)} path
     * @param  {(Array|Object)=}       keys
     * @param  {Object=}               options
     * @return {!RegExp}
     */
    function pathToRegexp (path, keys, options) {
        if (!isarray(keys)) {
            options = /** @type {!Object} */ (keys || options);
            keys = [];
        }

        options = options || {};

        if (path instanceof RegExp) {
            return regexpToRegexp(path, /** @type {!Array} */ (keys))
        }

        if (isarray(path)) {
            return arrayToRegexp(/** @type {!Array} */ (path), /** @type {!Array} */ (keys), options)
        }

        return stringToRegexp(/** @type {string} */ (path), /** @type {!Array} */ (keys), options)
    }
    pathToRegexp_1.parse = parse_1;
    pathToRegexp_1.compile = compile_1;
    pathToRegexp_1.tokensToFunction = tokensToFunction_1;
    pathToRegexp_1.tokensToRegExp = tokensToRegExp_1;

    /*  */

    // $flow-disable-line
    var regexpCompileCache = Object.create(null);

    function fillParams (
        path,
        params,
        routeMsg
    ) {
        params = params || {};
        try {
            var filler =
                regexpCompileCache[path] ||
                (regexpCompileCache[path] = pathToRegexp_1.compile(path));

            // Fix #2505 resolving asterisk routes { name: 'not-found', params: { pathMatch: '/not-found' }}
            // and fix #3106 so that you can work with location descriptor object having params.pathMatch equal to empty string
            if (typeof params.pathMatch === 'string') { params[0] = params.pathMatch; }

            return filler(params, { pretty: true })
        } catch (e) {
            {
                // Fix #3072 no warn if `pathMatch` is string
                warn(typeof params.pathMatch === 'string', ("missing param for " + routeMsg + ": " + (e.message)));
            }
            return ''
        } finally {
            // delete the 0 if it was added
            delete params[0];
        }
    }

    /*  */

    function normalizeLocation (
        raw,
        current,
        append,
        router
    ) {
        var next = typeof raw === 'string' ? { path: raw } : raw;
        // named target
        if (next._normalized) {
            return next
        } else if (next.name) {
            next = extend({}, raw);
            var params = next.params;
            if (params && typeof params === 'object') {
                next.params = extend({}, params);
            }
            return next
        }

        // relative params
        if (!next.path && next.params && current) {
            next = extend({}, next);
            next._normalized = true;
            var params$1 = extend(extend({}, current.params), next.params);
            if (current.name) {
                next.name = current.name;
                next.params = params$1;
            } else if (current.matched.length) {
                var rawPath = current.matched[current.matched.length - 1].path;
                next.path = fillParams(rawPath, params$1, ("path " + (current.path)));
            } else {
                warn(false, "relative params navigation requires a current route.");
            }
            return next
        }

        var parsedPath = parsePath(next.path || '');
        var basePath = (current && current.path) || '/';
        var path = parsedPath.path
            ? resolvePath(parsedPath.path, basePath, append || next.append)
            : basePath;

        var query = resolveQuery(
            parsedPath.query,
            next.query,
            router && router.options.parseQuery
        );

        var hash = next.hash || parsedPath.hash;
        if (hash && hash.charAt(0) !== '#') {
            hash = "#" + hash;
        }

        return {
            _normalized: true,
            path: path,
            query: query,
            hash: hash
        }
    }

    /*  */

    // work around weird flow bug
    var toTypes = [String, Object];
    var eventTypes = [String, Array];

    var noop = function () {};

    var warnedCustomSlot;
    var warnedTagProp;
    var warnedEventProp;

    var Link = {
        name: 'RouterLink',
        props: {
            to: {
                type: toTypes,
                required: true
            },
            tag: {
                type: String,
                default: 'a'
            },
            custom: Boolean,
            exact: Boolean,
            exactPath: Boolean,
            append: Boolean,
            replace: Boolean,
            activeClass: String,
            exactActiveClass: String,
            ariaCurrentValue: {
                type: String,
                default: 'page'
            },
            event: {
                type: eventTypes,
                default: 'click'
            }
        },
        render: function render (h) {
            var this$1 = this;

            var router = this.$router;
            var current = this.$route;
            var ref = router.resolve(
                this.to,
                current,
                this.append
            );
            var location = ref.location;
            var route = ref.route;
            var href = ref.href;

            var classes = {};
            var globalActiveClass = router.options.linkActiveClass;
            var globalExactActiveClass = router.options.linkExactActiveClass;
            // Support global empty active class
            var activeClassFallback =
                globalActiveClass == null ? 'router-link-active' : globalActiveClass;
            var exactActiveClassFallback =
                globalExactActiveClass == null
                    ? 'router-link-exact-active'
                    : globalExactActiveClass;
            var activeClass =
                this.activeClass == null ? activeClassFallback : this.activeClass;
            var exactActiveClass =
                this.exactActiveClass == null
                    ? exactActiveClassFallback
                    : this.exactActiveClass;

            var compareTarget = route.redirectedFrom
                ? createRoute(null, normalizeLocation(route.redirectedFrom), null, router)
                : route;

            classes[exactActiveClass] = isSameRoute(current, compareTarget, this.exactPath);
            classes[activeClass] = this.exact || this.exactPath
                ? classes[exactActiveClass]
                : isIncludedRoute(current, compareTarget);

            var ariaCurrentValue = classes[exactActiveClass] ? this.ariaCurrentValue : null;

            var handler = function (e) {
                if (guardEvent(e)) {
                    if (this$1.replace) {
                        router.replace(location, noop);
                    } else {
                        router.push(location, noop);
                    }
                }
            };

            var on = { click: guardEvent };
            if (Array.isArray(this.event)) {
                this.event.forEach(function (e) {
                    on[e] = handler;
                });
            } else {
                on[this.event] = handler;
            }

            var data = { class: classes };

            var scopedSlot =
                !this.$scopedSlots.$hasNormal &&
                this.$scopedSlots.default &&
                this.$scopedSlots.default({
                    href: href,
                    route: route,
                    navigate: handler,
                    isActive: classes[activeClass],
                    isExactActive: classes[exactActiveClass]
                });

            if (scopedSlot) {
                if ( !this.custom) {
                    !warnedCustomSlot && warn(false, 'In Vue Router 4, the v-slot API will by default wrap its content with an <a> element. Use the custom prop to remove this warning:\n<router-link v-slot="{ navigate, href }" custom></router-link>\n');
                    warnedCustomSlot = true;
                }
                if (scopedSlot.length === 1) {
                    return scopedSlot[0]
                } else if (scopedSlot.length > 1 || !scopedSlot.length) {
                    {
                        warn(
                            false,
                            ("<router-link> with to=\"" + (this.to) + "\" is trying to use a scoped slot but it didn't provide exactly one child. Wrapping the content with a span element.")
                        );
                    }
                    return scopedSlot.length === 0 ? h() : h('span', {}, scopedSlot)
                }
            }

            {
                if ('tag' in this.$options.propsData && !warnedTagProp) {
                    warn(
                        false,
                        "<router-link>'s tag prop is deprecated and has been removed in Vue Router 4. Use the v-slot API to remove this warning: https://next.router.vuejs.org/guide/migration/#removal-of-event-and-tag-props-in-router-link."
                    );
                    warnedTagProp = true;
                }
                if ('event' in this.$options.propsData && !warnedEventProp) {
                    warn(
                        false,
                        "<router-link>'s event prop is deprecated and has been removed in Vue Router 4. Use the v-slot API to remove this warning: https://next.router.vuejs.org/guide/migration/#removal-of-event-and-tag-props-in-router-link."
                    );
                    warnedEventProp = true;
                }
            }

            if (this.tag === 'a') {
                data.on = on;
                data.attrs = { href: href, 'aria-current': ariaCurrentValue };
            } else {
                // find the first <a> child and apply listener and href
                var a = findAnchor(this.$slots.default);
                if (a) {
                    // in case the <a> is a static node
                    a.isStatic = false;
                    var aData = (a.data = extend({}, a.data));
                    aData.on = aData.on || {};
                    // transform existing events in both objects into arrays so we can push later
                    for (var event in aData.on) {
                        var handler$1 = aData.on[event];
                        if (event in on) {
                            aData.on[event] = Array.isArray(handler$1) ? handler$1 : [handler$1];
                        }
                    }
                    // append new listeners for router-link
                    for (var event$1 in on) {
                        if (event$1 in aData.on) {
                            // on[event] is always a function
                            aData.on[event$1].push(on[event$1]);
                        } else {
                            aData.on[event$1] = handler;
                        }
                    }

                    var aAttrs = (a.data.attrs = extend({}, a.data.attrs));
                    aAttrs.href = href;
                    aAttrs['aria-current'] = ariaCurrentValue;
                } else {
                    // doesn't have <a> child, apply listener to self
                    data.on = on;
                }
            }

            return h(this.tag, data, this.$slots.default)
        }
    };

    function guardEvent (e) {
        // don't redirect with control keys
        if (e.metaKey || e.altKey || e.ctrlKey || e.shiftKey) { return }
        // don't redirect when preventDefault called
        if (e.defaultPrevented) { return }
        // don't redirect on right click
        if (e.button !== undefined && e.button !== 0) { return }
        // don't redirect if `target="_blank"`
        if (e.currentTarget && e.currentTarget.getAttribute) {
            var target = e.currentTarget.getAttribute('target');
            if (/\b_blank\b/i.test(target)) { return }
        }
        // this may be a Weex event which doesn't have this method
        if (e.preventDefault) {
            e.preventDefault();
        }
        return true
    }

    function findAnchor (children) {
        if (children) {
            var child;
            for (var i = 0; i < children.length; i++) {
                child = children[i];
                if (child.tag === 'a') {
                    return child
                }
                if (child.children && (child = findAnchor(child.children))) {
                    return child
                }
            }
        }
    }

    var _Vue;

    function install (Vue) {
        if (install.installed && _Vue === Vue) { return }
        install.installed = true;

        _Vue = Vue;

        var isDef = function (v) { return v !== undefined; };

        var registerInstance = function (vm, callVal) {
            var i = vm.$options._parentVnode;
            if (isDef(i) && isDef(i = i.data) && isDef(i = i.registerRouteInstance)) {
                i(vm, callVal);
            }
        };

        Vue.mixin({
            beforeCreate: function beforeCreate () {
                if (isDef(this.$options.router)) {
                    this._routerRoot = this;
                    this._router = this.$options.router;
                    this._router.init(this);
                    Vue.util.defineReactive(this, '_route', this._router.history.current);
                } else {
                    this._routerRoot = (this.$parent && this.$parent._routerRoot) || this;
                }
                registerInstance(this, this);
            },
            destroyed: function destroyed () {
                registerInstance(this);
            }
        });

        Object.defineProperty(Vue.prototype, '$router', {
            get: function get () { return this._routerRoot._router }
        });

        Object.defineProperty(Vue.prototype, '$route', {
            get: function get () { return this._routerRoot._route }
        });

        Vue.component('RouterView', View);
        Vue.component('RouterLink', Link);

        var strats = Vue.config.optionMergeStrategies;
        // use the same hook merging strategy for route hooks
        strats.beforeRouteEnter = strats.beforeRouteLeave = strats.beforeRouteUpdate = strats.created;
    }

    /*  */

    var inBrowser = typeof window !== 'undefined';

    /*  */

    function createRouteMap (
        routes,
        oldPathList,
        oldPathMap,
        oldNameMap,
        parentRoute
    ) {
        // the path list is used to control path matching priority
        var pathList = oldPathList || [];
        // $flow-disable-line
        var pathMap = oldPathMap || Object.create(null);
        // $flow-disable-line
        var nameMap = oldNameMap || Object.create(null);

        routes.forEach(function (route) {
            addRouteRecord(pathList, pathMap, nameMap, route, parentRoute);
        });

        // ensure wildcard routes are always at the end
        for (var i = 0, l = pathList.length; i < l; i++) {
            if (pathList[i] === '*') {
                pathList.push(pathList.splice(i, 1)[0]);
                l--;
                i--;
            }
        }

        {
            // warn if routes do not include leading slashes
            var found = pathList
            // check for missing leading slash
                .filter(function (path) { return path && path.charAt(0) !== '*' && path.charAt(0) !== '/'; });

            if (found.length > 0) {
                var pathNames = found.map(function (path) { return ("- " + path); }).join('\n');
                warn(false, ("Non-nested routes must include a leading slash character. Fix the following routes: \n" + pathNames));
            }
        }

        return {
            pathList: pathList,
            pathMap: pathMap,
            nameMap: nameMap
        }
    }

    function addRouteRecord (
        pathList,
        pathMap,
        nameMap,
        route,
        parent,
        matchAs
    ) {
        var path = route.path;
        var name = route.name;
        {
            assert(path != null, "\"path\" is required in a route configuration.");
            assert(
                typeof route.component !== 'string',
                "route config \"component\" for path: " + (String(
                path || name
                )) + " cannot be a " + "string id. Use an actual component instead."
            );

            warn(
                // eslint-disable-next-line no-control-regex
                !/[^\u0000-\u007F]+/.test(path),
                "Route with path \"" + path + "\" contains unencoded characters, make sure " +
                "your path is correctly encoded before passing it to the router. Use " +
                "encodeURI to encode static segments of your path."
            );
        }

        var pathToRegexpOptions =
            route.pathToRegexpOptions || {};
        var normalizedPath = normalizePath(path, parent, pathToRegexpOptions.strict);

        if (typeof route.caseSensitive === 'boolean') {
            pathToRegexpOptions.sensitive = route.caseSensitive;
        }

        var record = {
            path: normalizedPath,
            regex: compileRouteRegex(normalizedPath, pathToRegexpOptions),
            components: route.components || { default: route.component },
            alias: route.alias
                ? typeof route.alias === 'string'
                    ? [route.alias]
                    : route.alias
                : [],
            instances: {},
            enteredCbs: {},
            name: name,
            parent: parent,
            matchAs: matchAs,
            redirect: route.redirect,
            beforeEnter: route.beforeEnter,
            meta: route.meta || {},
            props:
                route.props == null
                    ? {}
                    : route.components
                    ? route.props
                    : { default: route.props }
        };

        if (route.children) {
            // Warn if route is named, does not redirect and has a default child route.
            // If users navigate to this route by name, the default child will
            // not be rendered (GH Issue #629)
            {
                if (
                    route.name &&
                    !route.redirect &&
                    route.children.some(function (child) { return /^\/?$/.test(child.path); })
                ) {
                    warn(
                        false,
                        "Named Route '" + (route.name) + "' has a default child route. " +
                        "When navigating to this named route (:to=\"{name: '" + (route.name) + "'\"), " +
                        "the default child route will not be rendered. Remove the name from " +
                        "this route and use the name of the default child route for named " +
                        "links instead."
                    );
                }
            }
            route.children.forEach(function (child) {
                var childMatchAs = matchAs
                    ? cleanPath((matchAs + "/" + (child.path)))
                    : undefined;
                addRouteRecord(pathList, pathMap, nameMap, child, record, childMatchAs);
            });
        }

        if (!pathMap[record.path]) {
            pathList.push(record.path);
            pathMap[record.path] = record;
        }

        if (route.alias !== undefined) {
            var aliases = Array.isArray(route.alias) ? route.alias : [route.alias];
            for (var i = 0; i < aliases.length; ++i) {
                var alias = aliases[i];
                if ( alias === path) {
                    warn(
                        false,
                        ("Found an alias with the same value as the path: \"" + path + "\". You have to remove that alias. It will be ignored in development.")
                    );
                    // skip in dev to make it work
                    continue
                }

                var aliasRoute = {
                    path: alias,
                    children: route.children
                };
                addRouteRecord(
                    pathList,
                    pathMap,
                    nameMap,
                    aliasRoute,
                    parent,
                    record.path || '/' // matchAs
                );
            }
        }

        if (name) {
            if (!nameMap[name]) {
                nameMap[name] = record;
            } else if ( !matchAs) {
                warn(
                    false,
                    "Duplicate named routes definition: " +
                    "{ name: \"" + name + "\", path: \"" + (record.path) + "\" }"
                );
            }
        }
    }

    function compileRouteRegex (
        path,
        pathToRegexpOptions
    ) {
        var regex = pathToRegexp_1(path, [], pathToRegexpOptions);
        {
            var keys = Object.create(null);
            regex.keys.forEach(function (key) {
                warn(
                    !keys[key.name],
                    ("Duplicate param keys in route with path: \"" + path + "\"")
                );
                keys[key.name] = true;
            });
        }
        return regex
    }

    function normalizePath (
        path,
        parent,
        strict
    ) {
        if (!strict) { path = path.replace(/\/$/, ''); }
        if (path[0] === '/') { return path }
        if (parent == null) { return path }
        return cleanPath(((parent.path) + "/" + path))
    }

    /*  */



    function createMatcher (
        routes,
        router
    ) {
        var ref = createRouteMap(routes);
        var pathList = ref.pathList;
        var pathMap = ref.pathMap;
        var nameMap = ref.nameMap;

        function addRoutes (routes) {
            createRouteMap(routes, pathList, pathMap, nameMap);
        }

        function addRoute (parentOrRoute, route) {
            var parent = (typeof parentOrRoute !== 'object') ? nameMap[parentOrRoute] : undefined;
            // $flow-disable-line
            createRouteMap([route || parentOrRoute], pathList, pathMap, nameMap, parent);

            // add aliases of parent
            if (parent) {
                createRouteMap(
                    // $flow-disable-line route is defined if parent is
                    parent.alias.map(function (alias) { return ({ path: alias, children: [route] }); }),
                    pathList,
                    pathMap,
                    nameMap,
                    parent
                );
            }
        }

        function getRoutes () {
            return pathList.map(function (path) { return pathMap[path]; })
        }

        function match (
            raw,
            currentRoute,
            redirectedFrom
        ) {
            var location = normalizeLocation(raw, currentRoute, false, router);
            var name = location.name;

            if (name) {
                var record = nameMap[name];
                {
                    warn(record, ("Route with name '" + name + "' does not exist"));
                }
                if (!record) { return _createRoute(null, location) }
                var paramNames = record.regex.keys
                    .filter(function (key) { return !key.optional; })
                    .map(function (key) { return key.name; });

                if (typeof location.params !== 'object') {
                    location.params = {};
                }

                if (currentRoute && typeof currentRoute.params === 'object') {
                    for (var key in currentRoute.params) {
                        if (!(key in location.params) && paramNames.indexOf(key) > -1) {
                            location.params[key] = currentRoute.params[key];
                        }
                    }
                }

                location.path = fillParams(record.path, location.params, ("named route \"" + name + "\""));
                return _createRoute(record, location, redirectedFrom)
            } else if (location.path) {
                location.params = {};
                for (var i = 0; i < pathList.length; i++) {
                    var path = pathList[i];
                    var record$1 = pathMap[path];
                    if (matchRoute(record$1.regex, location.path, location.params)) {
                        return _createRoute(record$1, location, redirectedFrom)
                    }
                }
            }
            // no match
            return _createRoute(null, location)
        }

        function redirect (
            record,
            location
        ) {
            var originalRedirect = record.redirect;
            var redirect = typeof originalRedirect === 'function'
                ? originalRedirect(createRoute(record, location, null, router))
                : originalRedirect;

            if (typeof redirect === 'string') {
                redirect = { path: redirect };
            }

            if (!redirect || typeof redirect !== 'object') {
                {
                    warn(
                        false, ("invalid redirect option: " + (JSON.stringify(redirect)))
                    );
                }
                return _createRoute(null, location)
            }

            var re = redirect;
            var name = re.name;
            var path = re.path;
            var query = location.query;
            var hash = location.hash;
            var params = location.params;
            query = re.hasOwnProperty('query') ? re.query : query;
            hash = re.hasOwnProperty('hash') ? re.hash : hash;
            params = re.hasOwnProperty('params') ? re.params : params;

            if (name) {
                // resolved named direct
                var targetRecord = nameMap[name];
                {
                    assert(targetRecord, ("redirect failed: named route \"" + name + "\" not found."));
                }
                return match({
                    _normalized: true,
                    name: name,
                    query: query,
                    hash: hash,
                    params: params
                }, undefined, location)
            } else if (path) {
                // 1. resolve relative redirect
                var rawPath = resolveRecordPath(path, record);
                // 2. resolve params
                var resolvedPath = fillParams(rawPath, params, ("redirect route with path \"" + rawPath + "\""));
                // 3. rematch with existing query and hash
                return match({
                    _normalized: true,
                    path: resolvedPath,
                    query: query,
                    hash: hash
                }, undefined, location)
            } else {
                {
                    warn(false, ("invalid redirect option: " + (JSON.stringify(redirect))));
                }
                return _createRoute(null, location)
            }
        }

        function alias (
            record,
            location,
            matchAs
        ) {
            var aliasedPath = fillParams(matchAs, location.params, ("aliased route with path \"" + matchAs + "\""));
            var aliasedMatch = match({
                _normalized: true,
                path: aliasedPath
            });
            if (aliasedMatch) {
                var matched = aliasedMatch.matched;
                var aliasedRecord = matched[matched.length - 1];
                location.params = aliasedMatch.params;
                return _createRoute(aliasedRecord, location)
            }
            return _createRoute(null, location)
        }

        function _createRoute (
            record,
            location,
            redirectedFrom
        ) {
            if (record && record.redirect) {
                return redirect(record, redirectedFrom || location)
            }
            if (record && record.matchAs) {
                return alias(record, location, record.matchAs)
            }
            return createRoute(record, location, redirectedFrom, router)
        }

        return {
            match: match,
            addRoute: addRoute,
            getRoutes: getRoutes,
            addRoutes: addRoutes
        }
    }

    function matchRoute (
        regex,
        path,
        params
    ) {
        var m = path.match(regex);

        if (!m) {
            return false
        } else if (!params) {
            return true
        }

        for (var i = 1, len = m.length; i < len; ++i) {
            var key = regex.keys[i - 1];
            if (key) {
                // Fix #1994: using * with props: true generates a param named 0
                params[key.name || 'pathMatch'] = typeof m[i] === 'string' ? decode(m[i]) : m[i];
            }
        }

        return true
    }

    function resolveRecordPath (path, record) {
        return resolvePath(path, record.parent ? record.parent.path : '/', true)
    }

    /*  */

    // use User Timing api (if present) for more accurate key precision
    var Time =
        inBrowser && window.performance && window.performance.now
            ? window.performance
            : Date;

    function genStateKey () {
        return Time.now().toFixed(3)
    }

    var _key = genStateKey();

    function getStateKey () {
        return _key
    }

    function setStateKey (key) {
        return (_key = key)
    }

    /*  */

    var positionStore = Object.create(null);

    function setupScroll () {
        // Prevent browser scroll behavior on History popstate
        if ('scrollRestoration' in window.history) {
            window.history.scrollRestoration = 'manual';
        }
        // Fix for #1585 for Firefox
        // Fix for #2195 Add optional third attribute to workaround a bug in safari https://bugs.webkit.org/show_bug.cgi?id=182678
        // Fix for #2774 Support for apps loaded from Windows file shares not mapped to network drives: replaced location.origin with
        // window.location.protocol + '//' + window.location.host
        // location.host contains the port and location.hostname doesn't
        var protocolAndPath = window.location.protocol + '//' + window.location.host;
        var absolutePath = window.location.href.replace(protocolAndPath, '');
        // preserve existing history state as it could be overriden by the user
        var stateCopy = extend({}, window.history.state);
        stateCopy.key = getStateKey();
        window.history.replaceState(stateCopy, '', absolutePath);
        window.addEventListener('popstate', handlePopState);
        return function () {
            window.removeEventListener('popstate', handlePopState);
        }
    }

    function handleScroll (
        router,
        to,
        from,
        isPop
    ) {
        if (!router.app) {
            return
        }

        var behavior = router.options.scrollBehavior;
        if (!behavior) {
            return
        }

        {
            assert(typeof behavior === 'function', "scrollBehavior must be a function");
        }

        // wait until re-render finishes before scrolling
        router.app.$nextTick(function () {
            var position = getScrollPosition();
            var shouldScroll = behavior.call(
                router,
                to,
                from,
                isPop ? position : null
            );

            if (!shouldScroll) {
                return
            }

            if (typeof shouldScroll.then === 'function') {
                shouldScroll
                    .then(function (shouldScroll) {
                        scrollToPosition((shouldScroll), position);
                    })
                    .catch(function (err) {
                        {
                            assert(false, err.toString());
                        }
                    });
            } else {
                scrollToPosition(shouldScroll, position);
            }
        });
    }

    function saveScrollPosition () {
        var key = getStateKey();
        if (key) {
            positionStore[key] = {
                x: window.pageXOffset,
                y: window.pageYOffset
            };
        }
    }

    function handlePopState (e) {
        saveScrollPosition();
        if (e.state && e.state.key) {
            setStateKey(e.state.key);
        }
    }

    function getScrollPosition () {
        var key = getStateKey();
        if (key) {
            return positionStore[key]
        }
    }

    function getElementPosition (el, offset) {
        var docEl = document.documentElement;
        var docRect = docEl.getBoundingClientRect();
        var elRect = el.getBoundingClientRect();
        return {
            x: elRect.left - docRect.left - offset.x,
            y: elRect.top - docRect.top - offset.y
        }
    }

    function isValidPosition (obj) {
        return isNumber(obj.x) || isNumber(obj.y)
    }

    function normalizePosition (obj) {
        return {
            x: isNumber(obj.x) ? obj.x : window.pageXOffset,
            y: isNumber(obj.y) ? obj.y : window.pageYOffset
        }
    }

    function normalizeOffset (obj) {
        return {
            x: isNumber(obj.x) ? obj.x : 0,
            y: isNumber(obj.y) ? obj.y : 0
        }
    }

    function isNumber (v) {
        return typeof v === 'number'
    }

    var hashStartsWithNumberRE = /^#\d/;

    function scrollToPosition (shouldScroll, position) {
        var isObject = typeof shouldScroll === 'object';
        if (isObject && typeof shouldScroll.selector === 'string') {
            // getElementById would still fail if the selector contains a more complicated query like #main[data-attr]
            // but at the same time, it doesn't make much sense to select an element with an id and an extra selector
            var el = hashStartsWithNumberRE.test(shouldScroll.selector) // $flow-disable-line
                ? document.getElementById(shouldScroll.selector.slice(1)) // $flow-disable-line
                : document.querySelector(shouldScroll.selector);

            if (el) {
                var offset =
                    shouldScroll.offset && typeof shouldScroll.offset === 'object'
                        ? shouldScroll.offset
                        : {};
                offset = normalizeOffset(offset);
                position = getElementPosition(el, offset);
            } else if (isValidPosition(shouldScroll)) {
                position = normalizePosition(shouldScroll);
            }
        } else if (isObject && isValidPosition(shouldScroll)) {
            position = normalizePosition(shouldScroll);
        }

        if (position) {
            // $flow-disable-line
            if ('scrollBehavior' in document.documentElement.style) {
                window.scrollTo({
                    left: position.x,
                    top: position.y,
                    // $flow-disable-line
                    behavior: shouldScroll.behavior
                });
            } else {
                window.scrollTo(position.x, position.y);
            }
        }
    }

    /*  */

    var supportsPushState =
        inBrowser &&
        (function () {
            var ua = window.navigator.userAgent;

            if (
                (ua.indexOf('Android 2.') !== -1 || ua.indexOf('Android 4.0') !== -1) &&
                ua.indexOf('Mobile Safari') !== -1 &&
                ua.indexOf('Chrome') === -1 &&
                ua.indexOf('Windows Phone') === -1
            ) {
                return false
            }

            return window.history && typeof window.history.pushState === 'function'
        })();

    function pushState (url, replace) {
        saveScrollPosition();
        // try...catch the pushState call to get around Safari
        // DOM Exception 18 where it limits to 100 pushState calls
        var history = window.history;
        try {
            if (replace) {
                // preserve existing history state as it could be overriden by the user
                var stateCopy = extend({}, history.state);
                stateCopy.key = getStateKey();
                history.replaceState(stateCopy, '', url);
            } else {
                history.pushState({ key: setStateKey(genStateKey()) }, '', url);
            }
        } catch (e) {
            window.location[replace ? 'replace' : 'assign'](url);
        }
    }

    function replaceState (url) {
        pushState(url, true);
    }

    /*  */

    function runQueue (queue, fn, cb) {
        var step = function (index) {
            if (index >= queue.length) {
                cb();
            } else {
                if (queue[index]) {
                    fn(queue[index], function () {
                        step(index + 1);
                    });
                } else {
                    step(index + 1);
                }
            }
        };
        step(0);
    }

    // When changing thing, also edit router.d.ts
    var NavigationFailureType = {
        redirected: 2,
        aborted: 4,
        cancelled: 8,
        duplicated: 16
    };

    function createNavigationRedirectedError (from, to) {
        return createRouterError(
            from,
            to,
            NavigationFailureType.redirected,
            ("Redirected when going from \"" + (from.fullPath) + "\" to \"" + (stringifyRoute(
                to
            )) + "\" via a navigation guard.")
        )
    }

    function createNavigationDuplicatedError (from, to) {
        var error = createRouterError(
            from,
            to,
            NavigationFailureType.duplicated,
            ("Avoided redundant navigation to current location: \"" + (from.fullPath) + "\".")
        );
        // backwards compatible with the first introduction of Errors
        error.name = 'NavigationDuplicated';
        return error
    }

    function createNavigationCancelledError (from, to) {
        return createRouterError(
            from,
            to,
            NavigationFailureType.cancelled,
            ("Navigation cancelled from \"" + (from.fullPath) + "\" to \"" + (to.fullPath) + "\" with a new navigation.")
        )
    }

    function createNavigationAbortedError (from, to) {
        return createRouterError(
            from,
            to,
            NavigationFailureType.aborted,
            ("Navigation aborted from \"" + (from.fullPath) + "\" to \"" + (to.fullPath) + "\" via a navigation guard.")
        )
    }

    function createRouterError (from, to, type, message) {
        var error = new Error(message);
        error._isRouter = true;
        error.from = from;
        error.to = to;
        error.type = type;

        return error
    }

    var propertiesToLog = ['params', 'query', 'hash'];

    function stringifyRoute (to) {
        if (typeof to === 'string') { return to }
        if ('path' in to) { return to.path }
        var location = {};
        propertiesToLog.forEach(function (key) {
            if (key in to) { location[key] = to[key]; }
        });
        return JSON.stringify(location, null, 2)
    }

    function isError (err) {
        return Object.prototype.toString.call(err).indexOf('Error') > -1
    }

    function isNavigationFailure (err, errorType) {
        return (
            isError(err) &&
            err._isRouter &&
            (errorType == null || err.type === errorType)
        )
    }

    /*  */

    function resolveAsyncComponents (matched) {
        return function (to, from, next) {
            var hasAsync = false;
            var pending = 0;
            var error = null;

            flatMapComponents(matched, function (def, _, match, key) {
                // if it's a function and doesn't have cid attached,
                // assume it's an async component resolve function.
                // we are not using Vue's default async resolving mechanism because
                // we want to halt the navigation until the incoming component has been
                // resolved.
                if (typeof def === 'function' && def.cid === undefined) {
                    hasAsync = true;
                    pending++;

                    var resolve = once(function (resolvedDef) {
                        if (isESModule(resolvedDef)) {
                            resolvedDef = resolvedDef.default;
                        }
                        // save resolved on async factory in case it's used elsewhere
                        def.resolved = typeof resolvedDef === 'function'
                            ? resolvedDef
                            : _Vue.extend(resolvedDef);
                        match.components[key] = resolvedDef;
                        pending--;
                        if (pending <= 0) {
                            next();
                        }
                    });

                    var reject = once(function (reason) {
                        var msg = "Failed to resolve async component " + key + ": " + reason;
                        warn(false, msg);
                        if (!error) {
                            error = isError(reason)
                                ? reason
                                : new Error(msg);
                            next(error);
                        }
                    });

                    var res;
                    try {
                        res = def(resolve, reject);
                    } catch (e) {
                        reject(e);
                    }
                    if (res) {
                        if (typeof res.then === 'function') {
                            res.then(resolve, reject);
                        } else {
                            // new syntax in Vue 2.3
                            var comp = res.component;
                            if (comp && typeof comp.then === 'function') {
                                comp.then(resolve, reject);
                            }
                        }
                    }
                }
            });

            if (!hasAsync) { next(); }
        }
    }

    function flatMapComponents (
        matched,
        fn
    ) {
        return flatten(matched.map(function (m) {
            return Object.keys(m.components).map(function (key) { return fn(
                m.components[key],
                m.instances[key],
                m, key
            ); })
        }))
    }

    function flatten (arr) {
        return Array.prototype.concat.apply([], arr)
    }

    var hasSymbol =
        typeof Symbol === 'function' &&
        typeof Symbol.toStringTag === 'symbol';

    function isESModule (obj) {
        return obj.__esModule || (hasSymbol && obj[Symbol.toStringTag] === 'Module')
    }

    // in Webpack 2, require.ensure now also returns a Promise
    // so the resolve/reject functions may get called an extra time
    // if the user uses an arrow function shorthand that happens to
    // return that Promise.
    function once (fn) {
        var called = false;
        return function () {
            var args = [], len = arguments.length;
            while ( len-- ) args[ len ] = arguments[ len ];

            if (called) { return }
            called = true;
            return fn.apply(this, args)
        }
    }

    /*  */

    var History = function History (router, base) {
        this.router = router;
        this.base = normalizeBase(base);
        // start with a route object that stands for "nowhere"
        this.current = START;
        this.pending = null;
        this.ready = false;
        this.readyCbs = [];
        this.readyErrorCbs = [];
        this.errorCbs = [];
        this.listeners = [];
    };

    History.prototype.listen = function listen (cb) {
        this.cb = cb;
    };

    History.prototype.onReady = function onReady (cb, errorCb) {
        if (this.ready) {
            cb();
        } else {
            this.readyCbs.push(cb);
            if (errorCb) {
                this.readyErrorCbs.push(errorCb);
            }
        }
    };

    History.prototype.onError = function onError (errorCb) {
        this.errorCbs.push(errorCb);
    };

    History.prototype.transitionTo = function transitionTo (
        location,
        onComplete,
        onAbort
    ) {
        var this$1 = this;

        var route;
        // catch redirect option https://github.com/vuejs/vue-router/issues/3201
        try {
            route = this.router.match(location, this.current);
        } catch (e) {
            this.errorCbs.forEach(function (cb) {
                cb(e);
            });
            // Exception should still be thrown
            throw e
        }
        var prev = this.current;
        this.confirmTransition(
            route,
            function () {
                this$1.updateRoute(route);
                onComplete && onComplete(route);
                this$1.ensureURL();
                this$1.router.afterHooks.forEach(function (hook) {
                    hook && hook(route, prev);
                });

                // fire ready cbs once
                if (!this$1.ready) {
                    this$1.ready = true;
                    this$1.readyCbs.forEach(function (cb) {
                        cb(route);
                    });
                }
            },
            function (err) {
                if (onAbort) {
                    onAbort(err);
                }
                if (err && !this$1.ready) {
                    // Initial redirection should not mark the history as ready yet
                    // because it's triggered by the redirection instead
                    // https://github.com/vuejs/vue-router/issues/3225
                    // https://github.com/vuejs/vue-router/issues/3331
                    if (!isNavigationFailure(err, NavigationFailureType.redirected) || prev !== START) {
                        this$1.ready = true;
                        this$1.readyErrorCbs.forEach(function (cb) {
                            cb(err);
                        });
                    }
                }
            }
        );
    };

    History.prototype.confirmTransition = function confirmTransition (route, onComplete, onAbort) {
        var this$1 = this;

        var current = this.current;
        this.pending = route;
        var abort = function (err) {
            // changed after adding errors with
            // https://github.com/vuejs/vue-router/pull/3047 before that change,
            // redirect and aborted navigation would produce an err == null
            if (!isNavigationFailure(err) && isError(err)) {
                if (this$1.errorCbs.length) {
                    this$1.errorCbs.forEach(function (cb) {
                        cb(err);
                    });
                } else {
                    warn(false, 'uncaught error during route navigation:');
                    console.error(err);
                }
            }
            onAbort && onAbort(err);
        };
        var lastRouteIndex = route.matched.length - 1;
        var lastCurrentIndex = current.matched.length - 1;
        if (
            isSameRoute(route, current) &&
            // in the case the route map has been dynamically appended to
            lastRouteIndex === lastCurrentIndex &&
            route.matched[lastRouteIndex] === current.matched[lastCurrentIndex]
        ) {
            this.ensureURL();
            return abort(createNavigationDuplicatedError(current, route))
        }

        var ref = resolveQueue(
            this.current.matched,
            route.matched
        );
        var updated = ref.updated;
        var deactivated = ref.deactivated;
        var activated = ref.activated;

        var queue = [].concat(
            // in-component leave guards
            extractLeaveGuards(deactivated),
            // global before hooks
            this.router.beforeHooks,
            // in-component update hooks
            extractUpdateHooks(updated),
            // in-config enter guards
            activated.map(function (m) { return m.beforeEnter; }),
            // async components
            resolveAsyncComponents(activated)
        );

        var iterator = function (hook, next) {
            if (this$1.pending !== route) {
                return abort(createNavigationCancelledError(current, route))
            }
            try {
                hook(route, current, function (to) {
                    if (to === false) {
                        // next(false) -> abort navigation, ensure current URL
                        this$1.ensureURL(true);
                        abort(createNavigationAbortedError(current, route));
                    } else if (isError(to)) {
                        this$1.ensureURL(true);
                        abort(to);
                    } else if (
                        typeof to === 'string' ||
                        (typeof to === 'object' &&
                            (typeof to.path === 'string' || typeof to.name === 'string'))
                    ) {
                        // next('/') or next({ path: '/' }) -> redirect
                        abort(createNavigationRedirectedError(current, route));
                        if (typeof to === 'object' && to.replace) {
                            this$1.replace(to);
                        } else {
                            this$1.push(to);
                        }
                    } else {
                        // confirm transition and pass on the value
                        next(to);
                    }
                });
            } catch (e) {
                abort(e);
            }
        };

        runQueue(queue, iterator, function () {
            // wait until async components are resolved before
            // extracting in-component enter guards
            var enterGuards = extractEnterGuards(activated);
            var queue = enterGuards.concat(this$1.router.resolveHooks);
            runQueue(queue, iterator, function () {
                if (this$1.pending !== route) {
                    return abort(createNavigationCancelledError(current, route))
                }
                this$1.pending = null;
                onComplete(route);
                if (this$1.router.app) {
                    this$1.router.app.$nextTick(function () {
                        handleRouteEntered(route);
                    });
                }
            });
        });
    };

    History.prototype.updateRoute = function updateRoute (route) {
        this.current = route;
        this.cb && this.cb(route);
    };

    History.prototype.setupListeners = function setupListeners () {
        // Default implementation is empty
    };

    History.prototype.teardown = function teardown () {
        // clean up event listeners
        // https://github.com/vuejs/vue-router/issues/2341
        this.listeners.forEach(function (cleanupListener) {
            cleanupListener();
        });
        this.listeners = [];

        // reset current history route
        // https://github.com/vuejs/vue-router/issues/3294
        this.current = START;
        this.pending = null;
    };

    function normalizeBase (base) {
        if (!base) {
            if (inBrowser) {
                // respect <base> tag
                var baseEl = document.querySelector('base');
                base = (baseEl && baseEl.getAttribute('href')) || '/';
                // strip full URL origin
                base = base.replace(/^https?:\/\/[^\/]+/, '');
            } else {
                base = '/';
            }
        }
        // make sure there's the starting slash
        if (base.charAt(0) !== '/') {
            base = '/' + base;
        }
        // remove trailing slash
        return base.replace(/\/$/, '')
    }

    function resolveQueue (
        current,
        next
    ) {
        var i;
        var max = Math.max(current.length, next.length);
        for (i = 0; i < max; i++) {
            if (current[i] !== next[i]) {
                break
            }
        }
        return {
            updated: next.slice(0, i),
            activated: next.slice(i),
            deactivated: current.slice(i)
        }
    }

    function extractGuards (
        records,
        name,
        bind,
        reverse
    ) {
        var guards = flatMapComponents(records, function (def, instance, match, key) {
            var guard = extractGuard(def, name);
            if (guard) {
                return Array.isArray(guard)
                    ? guard.map(function (guard) { return bind(guard, instance, match, key); })
                    : bind(guard, instance, match, key)
            }
        });
        return flatten(reverse ? guards.reverse() : guards)
    }

    function extractGuard (
        def,
        key
    ) {
        if (typeof def !== 'function') {
            // extend now so that global mixins are applied.
            def = _Vue.extend(def);
        }
        return def.options[key]
    }

    function extractLeaveGuards (deactivated) {
        return extractGuards(deactivated, 'beforeRouteLeave', bindGuard, true)
    }

    function extractUpdateHooks (updated) {
        return extractGuards(updated, 'beforeRouteUpdate', bindGuard)
    }

    function bindGuard (guard, instance) {
        if (instance) {
            return function boundRouteGuard () {
                return guard.apply(instance, arguments)
            }
        }
    }

    function extractEnterGuards (
        activated
    ) {
        return extractGuards(
            activated,
            'beforeRouteEnter',
            function (guard, _, match, key) {
                return bindEnterGuard(guard, match, key)
            }
        )
    }

    function bindEnterGuard (
        guard,
        match,
        key
    ) {
        return function routeEnterGuard (to, from, next) {
            return guard(to, from, function (cb) {
                if (typeof cb === 'function') {
                    if (!match.enteredCbs[key]) {
                        match.enteredCbs[key] = [];
                    }
                    match.enteredCbs[key].push(cb);
                }
                next(cb);
            })
        }
    }

    /*  */

    var HTML5History = /*@__PURE__*/(function (History) {
        function HTML5History (router, base) {
            History.call(this, router, base);

            this._startLocation = getLocation(this.base);
        }

        if ( History ) HTML5History.__proto__ = History;
        HTML5History.prototype = Object.create( History && History.prototype );
        HTML5History.prototype.constructor = HTML5History;

        HTML5History.prototype.setupListeners = function setupListeners () {
            var this$1 = this;

            if (this.listeners.length > 0) {
                return
            }

            var router = this.router;
            var expectScroll = router.options.scrollBehavior;
            var supportsScroll = supportsPushState && expectScroll;

            if (supportsScroll) {
                this.listeners.push(setupScroll());
            }

            var handleRoutingEvent = function () {
                var current = this$1.current;

                // Avoiding first `popstate` event dispatched in some browsers but first
                // history route not updated since async guard at the same time.
                var location = getLocation(this$1.base);
                if (this$1.current === START && location === this$1._startLocation) {
                    return
                }

                this$1.transitionTo(location, function (route) {
                    if (supportsScroll) {
                        handleScroll(router, route, current, true);
                    }
                });
            };
            window.addEventListener('popstate', handleRoutingEvent);
            this.listeners.push(function () {
                window.removeEventListener('popstate', handleRoutingEvent);
            });
        };

        HTML5History.prototype.go = function go (n) {
            window.history.go(n);
        };

        HTML5History.prototype.push = function push (location, onComplete, onAbort) {
            var this$1 = this;

            var ref = this;
            var fromRoute = ref.current;
            this.transitionTo(location, function (route) {
                pushState(cleanPath(this$1.base + route.fullPath));
                handleScroll(this$1.router, route, fromRoute, false);
                onComplete && onComplete(route);
            }, onAbort);
        };

        HTML5History.prototype.replace = function replace (location, onComplete, onAbort) {
            var this$1 = this;

            var ref = this;
            var fromRoute = ref.current;
            this.transitionTo(location, function (route) {
                replaceState(cleanPath(this$1.base + route.fullPath));
                handleScroll(this$1.router, route, fromRoute, false);
                onComplete && onComplete(route);
            }, onAbort);
        };

        HTML5History.prototype.ensureURL = function ensureURL (push) {
            if (getLocation(this.base) !== this.current.fullPath) {
                var current = cleanPath(this.base + this.current.fullPath);
                push ? pushState(current) : replaceState(current);
            }
        };

        HTML5History.prototype.getCurrentLocation = function getCurrentLocation () {
            return getLocation(this.base)
        };

        return HTML5History;
    }(History));

    function getLocation (base) {
        var path = window.location.pathname;
        if (base && path.toLowerCase().indexOf(base.toLowerCase()) === 0) {
            path = path.slice(base.length);
        }
        return (path || '/') + window.location.search + window.location.hash
    }

    /*  */

    var HashHistory = /*@__PURE__*/(function (History) {
        function HashHistory (router, base, fallback) {
            History.call(this, router, base);
            // check history fallback deeplinking
            if (fallback && checkFallback(this.base)) {
                return
            }
            ensureSlash();
        }

        if ( History ) HashHistory.__proto__ = History;
        HashHistory.prototype = Object.create( History && History.prototype );
        HashHistory.prototype.constructor = HashHistory;

        // this is delayed until the app mounts
        // to avoid the hashchange listener being fired too early
        HashHistory.prototype.setupListeners = function setupListeners () {
            var this$1 = this;

            if (this.listeners.length > 0) {
                return
            }

            var router = this.router;
            var expectScroll = router.options.scrollBehavior;
            var supportsScroll = supportsPushState && expectScroll;

            if (supportsScroll) {
                this.listeners.push(setupScroll());
            }

            var handleRoutingEvent = function () {
                var current = this$1.current;
                if (!ensureSlash()) {
                    return
                }
                this$1.transitionTo(getHash(), function (route) {
                    if (supportsScroll) {
                        handleScroll(this$1.router, route, current, true);
                    }
                    if (!supportsPushState) {
                        replaceHash(route.fullPath);
                    }
                });
            };
            var eventType = supportsPushState ? 'popstate' : 'hashchange';
            window.addEventListener(
                eventType,
                handleRoutingEvent
            );
            this.listeners.push(function () {
                window.removeEventListener(eventType, handleRoutingEvent);
            });
        };

        HashHistory.prototype.push = function push (location, onComplete, onAbort) {
            var this$1 = this;

            var ref = this;
            var fromRoute = ref.current;
            this.transitionTo(
                location,
                function (route) {
                    pushHash(route.fullPath);
                    handleScroll(this$1.router, route, fromRoute, false);
                    onComplete && onComplete(route);
                },
                onAbort
            );
        };

        HashHistory.prototype.replace = function replace (location, onComplete, onAbort) {
            var this$1 = this;

            var ref = this;
            var fromRoute = ref.current;
            this.transitionTo(
                location,
                function (route) {
                    replaceHash(route.fullPath);
                    handleScroll(this$1.router, route, fromRoute, false);
                    onComplete && onComplete(route);
                },
                onAbort
            );
        };

        HashHistory.prototype.go = function go (n) {
            window.history.go(n);
        };

        HashHistory.prototype.ensureURL = function ensureURL (push) {
            var current = this.current.fullPath;
            if (getHash() !== current) {
                push ? pushHash(current) : replaceHash(current);
            }
        };

        HashHistory.prototype.getCurrentLocation = function getCurrentLocation () {
            return getHash()
        };

        return HashHistory;
    }(History));

    function checkFallback (base) {
        var location = getLocation(base);
        if (!/^\/#/.test(location)) {
            window.location.replace(cleanPath(base + '/#' + location));
            return true
        }
    }

    function ensureSlash () {
        var path = getHash();
        if (path.charAt(0) === '/') {
            return true
        }
        replaceHash('/' + path);
        return false
    }

    function getHash () {
        // We can't use window.location.hash here because it's not
        // consistent across browsers - Firefox will pre-decode it!
        var href = window.location.href;
        var index = href.indexOf('#');
        // empty path
        if (index < 0) { return '' }

        href = href.slice(index + 1);

        return href
    }

    function getUrl (path) {
        var href = window.location.href;
        var i = href.indexOf('#');
        var base = i >= 0 ? href.slice(0, i) : href;
        return (base + "#" + path)
    }

    function pushHash (path) {
        if (supportsPushState) {
            pushState(getUrl(path));
        } else {
            window.location.hash = path;
        }
    }

    function replaceHash (path) {
        if (supportsPushState) {
            replaceState(getUrl(path));
        } else {
            window.location.replace(getUrl(path));
        }
    }

    /*  */

    var AbstractHistory = /*@__PURE__*/(function (History) {
        function AbstractHistory (router, base) {
            History.call(this, router, base);
            this.stack = [];
            this.index = -1;
        }

        if ( History ) AbstractHistory.__proto__ = History;
        AbstractHistory.prototype = Object.create( History && History.prototype );
        AbstractHistory.prototype.constructor = AbstractHistory;

        AbstractHistory.prototype.push = function push (location, onComplete, onAbort) {
            var this$1 = this;

            this.transitionTo(
                location,
                function (route) {
                    this$1.stack = this$1.stack.slice(0, this$1.index + 1).concat(route);
                    this$1.index++;
                    onComplete && onComplete(route);
                },
                onAbort
            );
        };

        AbstractHistory.prototype.replace = function replace (location, onComplete, onAbort) {
            var this$1 = this;

            this.transitionTo(
                location,
                function (route) {
                    this$1.stack = this$1.stack.slice(0, this$1.index).concat(route);
                    onComplete && onComplete(route);
                },
                onAbort
            );
        };

        AbstractHistory.prototype.go = function go (n) {
            var this$1 = this;

            var targetIndex = this.index + n;
            if (targetIndex < 0 || targetIndex >= this.stack.length) {
                return
            }
            var route = this.stack[targetIndex];
            this.confirmTransition(
                route,
                function () {
                    var prev = this$1.current;
                    this$1.index = targetIndex;
                    this$1.updateRoute(route);
                    this$1.router.afterHooks.forEach(function (hook) {
                        hook && hook(route, prev);
                    });
                },
                function (err) {
                    if (isNavigationFailure(err, NavigationFailureType.duplicated)) {
                        this$1.index = targetIndex;
                    }
                }
            );
        };

        AbstractHistory.prototype.getCurrentLocation = function getCurrentLocation () {
            var current = this.stack[this.stack.length - 1];
            return current ? current.fullPath : '/'
        };

        AbstractHistory.prototype.ensureURL = function ensureURL () {
            // noop
        };

        return AbstractHistory;
    }(History));

    /*  */

    var VueRouter = function VueRouter (options) {
        if ( options === void 0 ) options = {};

        this.app = null;
        this.apps = [];
        this.options = options;
        this.beforeHooks = [];
        this.resolveHooks = [];
        this.afterHooks = [];
        this.matcher = createMatcher(options.routes || [], this);

        var mode = options.mode || 'hash';
        this.fallback =
            mode === 'history' && !supportsPushState && options.fallback !== false;
        if (this.fallback) {
            mode = 'hash';
        }
        if (!inBrowser) {
            mode = 'abstract';
        }
        this.mode = mode;

        switch (mode) {
            case 'history':
                this.history = new HTML5History(this, options.base);
                break
            case 'hash':
                this.history = new HashHistory(this, options.base, this.fallback);
                break
            case 'abstract':
                this.history = new AbstractHistory(this, options.base);
                break
            default:
            {
                assert(false, ("invalid mode: " + mode));
            }
        }
    };

    var prototypeAccessors = { currentRoute: { configurable: true } };

    VueRouter.prototype.match = function match (raw, current, redirectedFrom) {
        return this.matcher.match(raw, current, redirectedFrom)
    };

    prototypeAccessors.currentRoute.get = function () {
        return this.history && this.history.current
    };

    VueRouter.prototype.init = function init (app /* Vue component instance */) {
        var this$1 = this;


        assert(
            install.installed,
            "not installed. Make sure to call `Vue.use(VueRouter)` " +
            "before creating root instance."
        );

        this.apps.push(app);

        // set up app destroyed handler
        // https://github.com/vuejs/vue-router/issues/2639
        app.$once('hook:destroyed', function () {
            // clean out app from this.apps array once destroyed
            var index = this$1.apps.indexOf(app);
            if (index > -1) { this$1.apps.splice(index, 1); }
            // ensure we still have a main app or null if no apps
            // we do not release the router so it can be reused
            if (this$1.app === app) { this$1.app = this$1.apps[0] || null; }

            if (!this$1.app) { this$1.history.teardown(); }
        });

        // main app previously initialized
        // return as we don't need to set up new history listener
        if (this.app) {
            return
        }

        this.app = app;

        var history = this.history;

        if (history instanceof HTML5History || history instanceof HashHistory) {
            var handleInitialScroll = function (routeOrError) {
                var from = history.current;
                var expectScroll = this$1.options.scrollBehavior;
                var supportsScroll = supportsPushState && expectScroll;

                if (supportsScroll && 'fullPath' in routeOrError) {
                    handleScroll(this$1, routeOrError, from, false);
                }
            };
            var setupListeners = function (routeOrError) {
                history.setupListeners();
                handleInitialScroll(routeOrError);
            };
            history.transitionTo(
                history.getCurrentLocation(),
                setupListeners,
                setupListeners
            );
        }

        history.listen(function (route) {
            this$1.apps.forEach(function (app) {
                app._route = route;
            });
        });
    };

    VueRouter.prototype.beforeEach = function beforeEach (fn) {
        return registerHook(this.beforeHooks, fn)
    };

    VueRouter.prototype.beforeResolve = function beforeResolve (fn) {
        return registerHook(this.resolveHooks, fn)
    };

    VueRouter.prototype.afterEach = function afterEach (fn) {
        return registerHook(this.afterHooks, fn)
    };

    VueRouter.prototype.onReady = function onReady (cb, errorCb) {
        this.history.onReady(cb, errorCb);
    };

    VueRouter.prototype.onError = function onError (errorCb) {
        this.history.onError(errorCb);
    };

    VueRouter.prototype.push = function push (location, onComplete, onAbort) {
        var this$1 = this;

        // $flow-disable-line
        if (!onComplete && !onAbort && typeof Promise !== 'undefined') {
            return new Promise(function (resolve, reject) {
                this$1.history.push(location, resolve, reject);
            })
        } else {
            this.history.push(location, onComplete, onAbort);
        }
    };

    VueRouter.prototype.replace = function replace (location, onComplete, onAbort) {
        var this$1 = this;

        // $flow-disable-line
        if (!onComplete && !onAbort && typeof Promise !== 'undefined') {
            return new Promise(function (resolve, reject) {
                this$1.history.replace(location, resolve, reject);
            })
        } else {
            this.history.replace(location, onComplete, onAbort);
        }
    };

    VueRouter.prototype.go = function go (n) {
        this.history.go(n);
    };

    VueRouter.prototype.back = function back () {
        this.go(-1);
    };

    VueRouter.prototype.forward = function forward () {
        this.go(1);
    };

    VueRouter.prototype.getMatchedComponents = function getMatchedComponents (to) {
        var route = to
            ? to.matched
                ? to
                : this.resolve(to).route
            : this.currentRoute;
        if (!route) {
            return []
        }
        return [].concat.apply(
            [],
            route.matched.map(function (m) {
                return Object.keys(m.components).map(function (key) {
                    return m.components[key]
                })
            })
        )
    };

    VueRouter.prototype.resolve = function resolve (
        to,
        current,
        append
    ) {
        current = current || this.history.current;
        var location = normalizeLocation(to, current, append, this);
        var route = this.match(location, current);
        var fullPath = route.redirectedFrom || route.fullPath;
        var base = this.history.base;
        var href = createHref(base, fullPath, this.mode);
        return {
            location: location,
            route: route,
            href: href,
            // for backwards compat
            normalizedTo: location,
            resolved: route
        }
    };

    VueRouter.prototype.getRoutes = function getRoutes () {
        return this.matcher.getRoutes()
    };

    VueRouter.prototype.addRoute = function addRoute (parentOrRoute, route) {
        this.matcher.addRoute(parentOrRoute, route);
        if (this.history.current !== START) {
            this.history.transitionTo(this.history.getCurrentLocation());
        }
    };

    VueRouter.prototype.addRoutes = function addRoutes (routes) {
        {
            warn(false, 'router.addRoutes() is deprecated and has been removed in Vue Router 4. Use router.addRoute() instead.');
        }
        this.matcher.addRoutes(routes);
        if (this.history.current !== START) {
            this.history.transitionTo(this.history.getCurrentLocation());
        }
    };

    Object.defineProperties( VueRouter.prototype, prototypeAccessors );

    function registerHook (list, fn) {
        list.push(fn);
        return function () {
            var i = list.indexOf(fn);
            if (i > -1) { list.splice(i, 1); }
        }
    }

    function createHref (base, fullPath, mode) {
        var path = mode === 'hash' ? '#' + fullPath : fullPath;
        return base ? cleanPath(base + '/' + path) : path
    }

    VueRouter.install = install;
    VueRouter.version = '3.5.1';
    VueRouter.isNavigationFailure = isNavigationFailure;
    VueRouter.NavigationFailureType = NavigationFailureType;
    VueRouter.START_LOCATION = START;

    if (inBrowser && window.Vue) {
        window.Vue.use(VueRouter);
    }

    return VueRouter;

})));