js工具代码封装(超长)1/3

 

/*!
 * Vue.js v2.5.16
 * (c) 2014-2018 Evan You
 * Released under the MIT License.
 */
(function (global, factory) {
    typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
        typeof define === 'function' && define.amd ? define(factory) :
            (global.Vue = factory());
}(this, (function () { 'use strict';

    /*  */

    var emptyObject = Object.freeze({});

// these helpers produces better vm code in JS engines due to their
// explicitness and function inlining
    function isUndef (v) {
        return v === undefined || v === null
    }

    function isDef (v) {
        return v !== undefined && v !== null
    }

    function isTrue (v) {
        return v === true
    }

    function isFalse (v) {
        return v === false
    }

    /**
     * Check if value is primitive
     */
    function isPrimitive (value) {
        return (
            typeof value === 'string' ||
            typeof value === 'number' ||
            // $flow-disable-line
            typeof value === 'symbol' ||
            typeof value === 'boolean'
        )
    }

    /**
     * Quick object check - this is primarily used to tell
     * Objects from primitive values when we know the value
     * is a JSON-compliant type.
     */
    function isObject (obj) {
        return obj !== null && typeof obj === 'object'
    }

    /**
     * Get the raw type string of a value e.g. [object Object]
     */
    var _toString = Object.prototype.toString;

    function toRawType (value) {
        return _toString.call(value).slice(8, -1)
    }

    /**
     * Strict object type check. Only returns true
     * for plain JavaScript objects.
     */
    function isPlainObject (obj) {
        return _toString.call(obj) === '[object Object]'
    }

    function isRegExp (v) {
        return _toString.call(v) === '[object RegExp]'
    }

    /**
     * Check if val is a valid array index.
     */
    function isValidArrayIndex (val) {
        var n = parseFloat(String(val));
        return n >= 0 && Math.floor(n) === n && isFinite(val)
    }

    /**
     * Convert a value to a string that is actually rendered.
     */
    function toString (val) {
        return val == null
            ? ''
            : typeof val === 'object'
            ? JSON.stringify(val, null, 2)
            : String(val)
    }

    /**
     * Convert a input value to a number for persistence.
     * If the conversion fails, return original string.
     */
    function toNumber (val) {
        var n = parseFloat(val);
        return isNaN(n) ? val : n
    }

    /**
     * Make a map and return a function for checking if a key
     * is in that map.
     */
    function makeMap (
        str,
        expectsLowerCase
    ) {
        var map = Object.create(null);
        var list = str.split(',');
        for (var i = 0; i < list.length; i++) {
            map[list[i]] = true;
        }
        return expectsLowerCase
            ? function (val) { return map[val.toLowerCase()]; }
            : function (val) { return map[val]; }
    }

    /**
     * Check if a tag is a built-in tag.
     */
    var isBuiltInTag = makeMap('slot,component', true);

    /**
     * Check if a attribute is a reserved attribute.
     */
    var isReservedAttribute = makeMap('key,ref,slot,slot-scope,is');

    /**
     * Remove an item from an array
     */
    function remove (arr, item) {
        if (arr.length) {
            var index = arr.indexOf(item);
            if (index > -1) {
                return arr.splice(index, 1)
            }
        }
    }

    /**
     * Check whether the object has the property.
     */
    var hasOwnProperty = Object.prototype.hasOwnProperty;
    function hasOwn (obj, key) {
        return hasOwnProperty.call(obj, key)
    }

    /**
     * Create a cached version of a pure function.
     */
    function cached (fn) {
        var cache = Object.create(null);
        return (function cachedFn (str) {
            var hit = cache[str];
            return hit || (cache[str] = fn(str))
        })
    }

    /**
     * Camelize a hyphen-delimited string.
     */
    var camelizeRE = /-(\w)/g;
    var camelize = cached(function (str) {
        return str.replace(camelizeRE, function (_, c) { return c ? c.toUpperCase() : ''; })
    });

    /**
     * Capitalize a string.
     */
    var capitalize = cached(function (str) {
        return str.charAt(0).toUpperCase() + str.slice(1)
    });

    /**
     * Hyphenate a camelCase string.
     */
    var hyphenateRE = /\B([A-Z])/g;
    var hyphenate = cached(function (str) {
        return str.replace(hyphenateRE, '-$1').toLowerCase()
    });

    /**
     * Simple bind polyfill for environments that do not support it... e.g.
     * PhantomJS 1.x. Technically we don't need this anymore since native bind is
     * now more performant in most browsers, but removing it would be breaking for
     * code that was able to run in PhantomJS 1.x, so this must be kept for
     * backwards compatibility.
     */

    /* istanbul ignore next */
    function polyfillBind (fn, ctx) {
        function boundFn (a) {
            var l = arguments.length;
            return l
                ? l > 1
                ? fn.apply(ctx, arguments)
                : fn.call(ctx, a)
                : fn.call(ctx)
        }

        boundFn._length = fn.length;
        return boundFn
    }

    function nativeBind (fn, ctx) {
        return fn.bind(ctx)
    }

    var bind = Function.prototype.bind
        ? nativeBind
        : polyfillBind;

    /**
     * Convert an Array-like object to a real Array.
     */
    function toArray (list, start) {
        start = start || 0;
        var i = list.length - start;
        var ret = new Array(i);
        while (i--) {
            ret[i] = list[i + start];
        }
        return ret
    }

    /**
     * Mix properties into target object.
     */
    function extend (to, _from) {
        for (var key in _from) {
            to[key] = _from[key];
        }
        return to
    }

    /**
     * Merge an Array of Objects into a single Object.
     */
    function toObject (arr) {
        var res = {};
        for (var i = 0; i < arr.length; i++) {
            if (arr[i]) {
                extend(res, arr[i]);
            }
        }
        return res
    }

    /**
     * Perform no operation.
     * Stubbing args to make Flow happy without leaving useless transpiled code
     * with ...rest (https://flow.org/blog/2017/05/07/Strict-Function-Call-Arity/)
     */
    function noop (a, b, c) {}

    /**
     * Always return false.
     */
    var no = function (a, b, c) { return false; };

    /**
     * Return same value
     */
    var identity = function (_) { return _; };

    /**
     * Generate a static keys string from compiler modules.
     */
    function genStaticKeys (modules) {
        return modules.reduce(function (keys, m) {
            return keys.concat(m.staticKeys || [])
        }, []).join(',')
    }

    /**
     * Check if two values are loosely equal - that is,
     * if they are plain objects, do they have the same shape?
     */
    function looseEqual (a, b) {
        if (a === b) { return true }
        var isObjectA = isObject(a);
        var isObjectB = isObject(b);
        if (isObjectA && isObjectB) {
            try {
                var isArrayA = Array.isArray(a);
                var isArrayB = Array.isArray(b);
                if (isArrayA && isArrayB) {
                    return a.length === b.length && a.every(function (e, i) {
                            return looseEqual(e, b[i])
                        })
                } else if (!isArrayA && !isArrayB) {
                    var keysA = Object.keys(a);
                    var keysB = Object.keys(b);
                    return keysA.length === keysB.length && keysA.every(function (key) {
                            return looseEqual(a[key], b[key])
                        })
                } else {
                    /* istanbul ignore next */
                    return false
                }
            } catch (e) {
                /* istanbul ignore next */
                return false
            }
        } else if (!isObjectA && !isObjectB) {
            return String(a) === String(b)
        } else {
            return false
        }
    }

    function looseIndexOf (arr, val) {
        for (var i = 0; i < arr.length; i++) {
            if (looseEqual(arr[i], val)) { return i }
        }
        return -1
    }

    /**
     * Ensure a function is called only once.
     */
    function once (fn) {
        var called = false;
        return function () {
            if (!called) {
                called = true;
                fn.apply(this, arguments);
            }
        }
    }

    var SSR_ATTR = 'data-server-rendered';

    var ASSET_TYPES = [
        'component',
        'directive',
        'filter'
    ];

    var LIFECYCLE_HOOKS = [
        'beforeCreate',
        'created',
        'beforeMount',
        'mounted',
        'beforeUpdate',
        'updated',
        'beforeDestroy',
        'destroyed',
        'activated',
        'deactivated',
        'errorCaptured'
    ];

    /*  */

    var config = ({
        /**
         * Option merge strategies (used in core/util/options)
         */
        // $flow-disable-line
        optionMergeStrategies: Object.create(null),

        /**
         * Whether to suppress warnings.
         */
        silent: false,

        /**
         * Show production mode tip message on boot?
         */
        productionTip: "development" !== 'production',

        /**
         * Whether to enable devtools
         */
        devtools: "development" !== 'production',

        /**
         * Whether to record perf
         */
        performance: false,

        /**
         * Error handler for watcher errors
         */
        errorHandler: null,

        /**
         * Warn handler for watcher warns
         */
        warnHandler: null,

        /**
         * Ignore certain custom elements
         */
        ignoredElements: [],

        /**
         * Custom user key aliases for v-on
         */
        // $flow-disable-line
        keyCodes: Object.create(null),

        /**
         * Check if a tag is reserved so that it cannot be registered as a
         * component. This is platform-dependent and may be overwritten.
         */
        isReservedTag: no,

        /**
         * Check if an attribute is reserved so that it cannot be used as a component
         * prop. This is platform-dependent and may be overwritten.
         */
        isReservedAttr: no,

        /**
         * Check if a tag is an unknown element.
         * Platform-dependent.
         */
        isUnknownElement: no,

        /**
         * Get the namespace of an element
         */
        getTagNamespace: noop,

        /**
         * Parse the real tag name for the specific platform.
         */
        parsePlatformTagName: identity,

        /**
         * Check if an attribute must be bound using property, e.g. value
         * Platform-dependent.
         */
        mustUseProp: no,

        /**
         * Exposed for legacy reasons
         */
        _lifecycleHooks: LIFECYCLE_HOOKS
    })

    /*  */

    /**
     * Check if a string starts with $ or _
     */
    function isReserved (str) {
        var c = (str + '').charCodeAt(0);
        return c === 0x24 || c === 0x5F
    }

    /**
     * Define a property.
     */
    function def (obj, key, val, enumerable) {
        Object.defineProperty(obj, key, {
            value: val,
            enumerable: !!enumerable,
            writable: true,
            configurable: true
        });
    }

    /**
     * Parse simple path.
     */
    var bailRE = /[^\w.$]/;
    function parsePath (path) {
        if (bailRE.test(path)) {
            return
        }
        var segments = path.split('.');
        return function (obj) {
            for (var i = 0; i < segments.length; i++) {
                if (!obj) { return }
                obj = obj[segments[i]];
            }
            return obj
        }
    }

    /*  */

// can we use __proto__?
    var hasProto = '__proto__' in {};

// Browser environment sniffing
    var inBrowser = typeof window !== 'undefined';
    var inWeex = typeof WXEnvironment !== 'undefined' && !!WXEnvironment.platform;
    var weexPlatform = inWeex && WXEnvironment.platform.toLowerCase();
    var UA = inBrowser && window.navigator.userAgent.toLowerCase();
    var isIE = UA && /msie|trident/.test(UA);
    var isIE9 = UA && UA.indexOf('msie 9.0') > 0;
    var isEdge = UA && UA.indexOf('edge/') > 0;
    var isAndroid = (UA && UA.indexOf('android') > 0) || (weexPlatform === 'android');
    var isIOS = (UA && /iphone|ipad|ipod|ios/.test(UA)) || (weexPlatform === 'ios');
    var isChrome = UA && /chrome\/\d+/.test(UA) && !isEdge;

// Firefox has a "watch" function on Object.prototype...
    var nativeWatch = ({}).watch;

    var supportsPassive = false;
    if (inBrowser) {
        try {
            var opts = {};
            Object.defineProperty(opts, 'passive', ({
                get: function get () {
                    /* istanbul ignore next */
                    supportsPassive = true;
                }
            })); // https://github.com/facebook/flow/issues/285
            window.addEventListener('test-passive', null, opts);
        } catch (e) {}
    }

// this needs to be lazy-evaled because vue may be required before
// vue-server-renderer can set VUE_ENV
    var _isServer;
    var isServerRendering = function () {
        if (_isServer === undefined) {
            /* istanbul ignore if */
            if (!inBrowser && !inWeex && typeof global !== 'undefined') {
                // detect presence of vue-server-renderer and avoid
                // Webpack shimming the process
                _isServer = global['process'].env.VUE_ENV === 'server';
            } else {
                _isServer = false;
            }
        }
        return _isServer
    };

// detect devtools
    var devtools = inBrowser && window.__VUE_DEVTOOLS_GLOBAL_HOOK__;

    /* istanbul ignore next */
    function isNative (Ctor) {
        return typeof Ctor === 'function' && /native code/.test(Ctor.toString())
    }

    var hasSymbol =
        typeof Symbol !== 'undefined' && isNative(Symbol) &&
        typeof Reflect !== 'undefined' && isNative(Reflect.ownKeys);

    var _Set;
    /* istanbul ignore if */ // $flow-disable-line
    if (typeof Set !== 'undefined' && isNative(Set)) {
        // use native Set when available.
        _Set = Set;
    } else {
        // a non-standard Set polyfill that only works with primitive keys.
        _Set = (function () {
            function Set () {
                this.set = Object.create(null);
            }
            Set.prototype.has = function has (key) {
                return this.set[key] === true
            };
            Set.prototype.add = function add (key) {
                this.set[key] = true;
            };
            Set.prototype.clear = function clear () {
                this.set = Object.create(null);
            };

            return Set;
        }());
    }

    /*  */

    var warn = noop;
    var tip = noop;
    var generateComponentTrace = (noop); // work around flow check
    var formatComponentName = (noop);

    {
        var hasConsole = typeof console !== 'undefined';
        var classifyRE = /(?:^|[-_])(\w)/g;
        var classify = function (str) { return str
            .replace(classifyRE, function (c) { return c.toUpperCase(); })
            .replace(/[-_]/g, ''); };

        warn = function (msg, vm) {
            var trace = vm ? generateComponentTrace(vm) : '';

            if (config.warnHandler) {
                config.warnHandler.call(null, msg, vm, trace);
            } else if (hasConsole && (!config.silent)) {
                console.error(("[Vue warn]: " + msg + trace));
            }
        };

        tip = function (msg, vm) {
            if (hasConsole && (!config.silent)) {
                console.warn("[Vue tip]: " + msg + (
                        vm ? generateComponentTrace(vm) : ''
                    ));
            }
        };

        formatComponentName = function (vm, includeFile) {
            if (vm.$root === vm) {
                return ''
            }
            var options = typeof vm === 'function' && vm.cid != null
                ? vm.options
                : vm._isVue
                ? vm.$options || vm.constructor.options
                : vm || {};
            var name = options.name || options._componentTag;
            var file = options.__file;
            if (!name && file) {
                var match = file.match(/([^/\\]+)\.vue$/);
                name = match && match[1];
            }

            return (
                (name ? ("<" + (classify(name)) + ">") : "") +
                (file && includeFile !== false ? (" at " + file) : '')
            )
        };

        var repeat = function (str, n) {
            var res = '';
            while (n) {
                if (n % 2 === 1) { res += str; }
                if (n > 1) { str += str; }
                n >>= 1;
            }
            return res
        };

        generateComponentTrace = function (vm) {
            if (vm._isVue && vm.$parent) {
                var tree = [];
                var currentRecursiveSequence = 0;
                while (vm) {
                    if (tree.length > 0) {
                        var last = tree[tree.length - 1];
                        if (last.constructor === vm.constructor) {
                            currentRecursiveSequence++;
                            vm = vm.$parent;
                            continue
                        } else if (currentRecursiveSequence > 0) {
                            tree[tree.length - 1] = [last, currentRecursiveSequence];
                            currentRecursiveSequence = 0;
                        }
                    }
                    tree.push(vm);
                    vm = vm.$parent;
                }
                return '\n\nfound in\n\n' + tree
                        .map(function (vm, i) { return ("" + (i === 0 ? '---> ' : repeat(' ', 5 + i * 2)) + (Array.isArray(vm)
                            ? ((formatComponentName(vm[0])) + "... (" + (vm[1]) + " recursive calls)")
                            : formatComponentName(vm))); })
                        .join('\n')
            } else {
                return ("\n\n(found in " + (formatComponentName(vm)) + ")")
            }
        };
    }

    /*  */


    var uid = 0;

    /**
     * A dep is an observable that can have multiple
     * directives subscribing to it.
     */
    var Dep = function Dep () {
        this.id = uid++;
        this.subs = [];
    };

    Dep.prototype.addSub = function addSub (sub) {
        this.subs.push(sub);
    };

    Dep.prototype.removeSub = function removeSub (sub) {
        remove(this.subs, sub);
    };

    Dep.prototype.depend = function depend () {
        if (Dep.target) {
            Dep.target.addDep(this);
        }
    };

    Dep.prototype.notify = function notify () {
        // stabilize the subscriber list first
        var subs = this.subs.slice();
        for (var i = 0, l = subs.length; i < l; i++) {
            subs[i].update();
        }
    };

// the current target watcher being evaluated.
// this is globally unique because there could be only one
// watcher being evaluated at any time.
    Dep.target = null;
    var targetStack = [];

    function pushTarget (_target) {
        if (Dep.target) { targetStack.push(Dep.target); }
        Dep.target = _target;
    }

    function popTarget () {
        Dep.target = targetStack.pop();
    }

    /*  */

    var VNode = function VNode (
        tag,
        data,
        children,
        text,
        elm,
        context,
        componentOptions,
        asyncFactory
    ) {
        this.tag = tag;
        this.data = data;
        this.children = children;
        this.text = text;
        this.elm = elm;
        this.ns = undefined;
        this.context = context;
        this.fnContext = undefined;
        this.fnOptions = undefined;
        this.fnScopeId = undefined;
        this.key = data && data.key;
        this.componentOptions = componentOptions;
        this.componentInstance = undefined;
        this.parent = undefined;
        this.raw = false;
        this.isStatic = false;
        this.isRootInsert = true;
        this.isComment = false;
        this.isCloned = false;
        this.isOnce = false;
        this.asyncFactory = asyncFactory;
        this.asyncMeta = undefined;
        this.isAsyncPlaceholder = false;
    };

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

// DEPRECATED: alias for componentInstance for backwards compat.
    /* istanbul ignore next */
    prototypeAccessors.child.get = function () {
        return this.componentInstance
    };

    Object.defineProperties( VNode.prototype, prototypeAccessors );

    var createEmptyVNode = function (text) {
        if ( text === void 0 ) text = '';

        var node = new VNode();
        node.text = text;
        node.isComment = true;
        return node
    };

    function createTextVNode (val) {
        return new VNode(undefined, undefined, undefined, String(val))
    }

// optimized shallow clone
// used for static nodes and slot nodes because they may be reused across
// multiple renders, cloning them avoids errors when DOM manipulations rely
// on their elm reference.
    function cloneVNode (vnode) {
        var cloned = new VNode(
            vnode.tag,
            vnode.data,
            vnode.children,
            vnode.text,
            vnode.elm,
            vnode.context,
            vnode.componentOptions,
            vnode.asyncFactory
        );
        cloned.ns = vnode.ns;
        cloned.isStatic = vnode.isStatic;
        cloned.key = vnode.key;
        cloned.isComment = vnode.isComment;
        cloned.fnContext = vnode.fnContext;
        cloned.fnOptions = vnode.fnOptions;
        cloned.fnScopeId = vnode.fnScopeId;
        cloned.isCloned = true;
        return cloned
    }

    /*
     * not type checking this file because flow doesn't play well with
     * dynamically accessing methods on Array prototype
     */

    var arrayProto = Array.prototype;
    var arrayMethods = Object.create(arrayProto);

    var methodsToPatch = [
        'push',
        'pop',
        'shift',
        'unshift',
        'splice',
        'sort',
        'reverse'
    ];

    /**
     * Intercept mutating methods and emit events
     */
    methodsToPatch.forEach(function (method) {
        // cache original method
        var original = arrayProto[method];
        def(arrayMethods, method, function mutator () {
            var args = [], len = arguments.length;
            while ( len-- ) args[ len ] = arguments[ len ];

            var result = original.apply(this, args);
            var ob = this.__ob__;
            var inserted;
            switch (method) {
                case 'push':
                case 'unshift':
                    inserted = args;
                    break
                case 'splice':
                    inserted = args.slice(2);
                    break
            }
            if (inserted) { ob.observeArray(inserted); }
            // notify change
            ob.dep.notify();
            return result
        });
    });

    /*  */

    var arrayKeys = Object.getOwnPropertyNames(arrayMethods);

    /**
     * In some cases we may want to disable observation inside a component's
     * update computation.
     */
    var shouldObserve = true;

    function toggleObserving (value) {
        shouldObserve = value;
    }

    /**
     * Observer class that is attached to each observed
     * object. Once attached, the observer converts the target
     * object's property keys into getter/setters that
     * collect dependencies and dispatch updates.
     */
    var Observer = function Observer (value) {
        this.value = value;
        this.dep = new Dep();
        this.vmCount = 0;
        def(value, '__ob__', this);
        if (Array.isArray(value)) {
            var augment = hasProto
                ? protoAugment
                : copyAugment;
            augment(value, arrayMethods, arrayKeys);
            this.observeArray(value);
        } else {
            this.walk(value);
        }
    };

    /**
     * Walk through each property and convert them into
     * getter/setters. This method should only be called when
     * value type is Object.
     */
    Observer.prototype.walk = function walk (obj) {
        var keys = Object.keys(obj);
        for (var i = 0; i < keys.length; i++) {
            defineReactive(obj, keys[i]);
        }
    };

    /**
     * Observe a list of Array items.
     */
    Observer.prototype.observeArray = function observeArray (items) {
        for (var i = 0, l = items.length; i < l; i++) {
            observe(items[i]);
        }
    };

// helpers

    /**
     * Augment an target Object or Array by intercepting
     * the prototype chain using __proto__
     */
    function protoAugment (target, src, keys) {
        /* eslint-disable no-proto */
        target.__proto__ = src;
        /* eslint-enable no-proto */
    }

    /**
     * Augment an target Object or Array by defining
     * hidden properties.
     */
    /* istanbul ignore next */
    function copyAugment (target, src, keys) {
        for (var i = 0, l = keys.length; i < l; i++) {
            var key = keys[i];
            def(target, key, src[key]);
        }
    }

    /**
     * Attempt to create an observer instance for a value,
     * returns the new observer if successfully observed,
     * or the existing observer if the value already has one.
     */
    function observe (value, asRootData) {
        if (!isObject(value) || value instanceof VNode) {
            return
        }
        var ob;
        if (hasOwn(value, '__ob__') && value.__ob__ instanceof Observer) {
            ob = value.__ob__;
        } else if (
            shouldObserve &&
            !isServerRendering() &&
            (Array.isArray(value) || isPlainObject(value)) &&
            Object.isExtensible(value) &&
            !value._isVue
        ) {
            ob = new Observer(value);
        }
        if (asRootData && ob) {
            ob.vmCount++;
        }
        return ob
    }

    /**
     * Define a reactive property on an Object.
     */
    function defineReactive (
        obj,
        key,
        val,
        customSetter,
        shallow
    ) {
        var dep = new Dep();

        var property = Object.getOwnPropertyDescriptor(obj, key);
        if (property && property.configurable === false) {
            return
        }

        // cater for pre-defined getter/setters
        var getter = property && property.get;
        if (!getter && arguments.length === 2) {
            val = obj[key];
        }
        var setter = property && property.set;

        var childOb = !shallow && observe(val);
        Object.defineProperty(obj, key, {
            enumerable: true,
            configurable: true,
            get: function reactiveGetter () {
                var value = getter ? getter.call(obj) : val;
                if (Dep.target) {
                    dep.depend();
                    if (childOb) {
                        childOb.dep.depend();
                        if (Array.isArray(value)) {
                            dependArray(value);
                        }
                    }
                }
                return value
            },
            set: function reactiveSetter (newVal) {
                var value = getter ? getter.call(obj) : val;
                /* eslint-disable no-self-compare */
                if (newVal === value || (newVal !== newVal && value !== value)) {
                    return
                }
                /* eslint-enable no-self-compare */
                if ("development" !== 'production' && customSetter) {
                    customSetter();
                }
                if (setter) {
                    setter.call(obj, newVal);
                } else {
                    val = newVal;
                }
                childOb = !shallow && observe(newVal);
                dep.notify();
            }
        });
    }

    /**
     * Set a property on an object. Adds the new property and
     * triggers change notification if the property doesn't
     * already exist.
     */
    function set (target, key, val) {
        if ("development" !== 'production' &&
            (isUndef(target) || isPrimitive(target))
        ) {
            warn(("Cannot set reactive property on undefined, null, or primitive value: " + ((target))));
        }
        if (Array.isArray(target) && isValidArrayIndex(key)) {
            target.length = Math.max(target.length, key);
            target.splice(key, 1, val);
            return val
        }
        if (key in target && !(key in Object.prototype)) {
            target[key] = val;
            return val
        }
        var ob = (target).__ob__;
        if (target._isVue || (ob && ob.vmCount)) {
            "development" !== 'production' && warn(
                'Avoid adding reactive properties to a Vue instance or its root $data ' +
                'at runtime - declare it upfront in the data option.'
            );
            return val
        }
        if (!ob) {
            target[key] = val;
            return val
        }
        defineReactive(ob.value, key, val);
        ob.dep.notify();
        return val
    }

    /**
     * Delete a property and trigger change if necessary.
     */
    function del (target, key) {
        if ("development" !== 'production' &&
            (isUndef(target) || isPrimitive(target))
        ) {
            warn(("Cannot delete reactive property on undefined, null, or primitive value: " + ((target))));
        }
        if (Array.isArray(target) && isValidArrayIndex(key)) {
            target.splice(key, 1);
            return
        }
        var ob = (target).__ob__;
        if (target._isVue || (ob && ob.vmCount)) {
            "development" !== 'production' && warn(
                'Avoid deleting properties on a Vue instance or its root $data ' +
                '- just set it to null.'
            );
            return
        }
        if (!hasOwn(target, key)) {
            return
        }
        delete target[key];
        if (!ob) {
            return
        }
        ob.dep.notify();
    }

    /**
     * Collect dependencies on array elements when the array is touched, since
     * we cannot intercept array element access like property getters.
     */
    function dependArray (value) {
        for (var e = (void 0), i = 0, l = value.length; i < l; i++) {
            e = value[i];
            e && e.__ob__ && e.__ob__.dep.depend();
            if (Array.isArray(e)) {
                dependArray(e);
            }
        }
    }

    /*  */

    /**
     * Option overwriting strategies are functions that handle
     * how to merge a parent option value and a child option
     * value into the final value.
     */
    var strats = config.optionMergeStrategies;

    /**
     * Options with restrictions
     */
    {
        strats.el = strats.propsData = function (parent, child, vm, key) {
            if (!vm) {
                warn(
                    "option \"" + key + "\" can only be used during instance " +
                    'creation with the `new` keyword.'
                );
            }
            return defaultStrat(parent, child)
        };
    }

    /**
     * Helper that recursively merges two data objects together.
     */
    function mergeData (to, from) {
        if (!from) { return to }
        var key, toVal, fromVal;
        var keys = Object.keys(from);
        for (var i = 0; i < keys.length; i++) {
            key = keys[i];
            toVal = to[key];
            fromVal = from[key];
            if (!hasOwn(to, key)) {
                set(to, key, fromVal);
            } else if (isPlainObject(toVal) && isPlainObject(fromVal)) {
                mergeData(toVal, fromVal);
            }
        }
        return to
    }

    /**
     * Data
     */
    function mergeDataOrFn (
        parentVal,
        childVal,
        vm
    ) {
        if (!vm) {
            // in a Vue.extend merge, both should be functions
            if (!childVal) {
                return parentVal
            }
            if (!parentVal) {
                return childVal
            }
            // when parentVal & childVal are both present,
            // we need to return a function that returns the
            // merged result of both functions... no need to
            // check if parentVal is a function here because
            // it has to be a function to pass previous merges.
            return function mergedDataFn () {
                return mergeData(
                    typeof childVal === 'function' ? childVal.call(this, this) : childVal,
                    typeof parentVal === 'function' ? parentVal.call(this, this) : parentVal
                )
            }
        } else {
            return function mergedInstanceDataFn () {
                // instance merge
                var instanceData = typeof childVal === 'function'
                    ? childVal.call(vm, vm)
                    : childVal;
                var defaultData = typeof parentVal === 'function'
                    ? parentVal.call(vm, vm)
                    : parentVal;
                if (instanceData) {
                    return mergeData(instanceData, defaultData)
                } else {
                    return defaultData
                }
            }
        }
    }

    strats.data = function (
        parentVal,
        childVal,
        vm
    ) {
        if (!vm) {
            if (childVal && typeof childVal !== 'function') {
                "development" !== 'production' && warn(
                    'The "data" option should be a function ' +
                    'that returns a per-instance value in component ' +
                    'definitions.',
                    vm
                );

                return parentVal
            }
            return mergeDataOrFn(parentVal, childVal)
        }

        return mergeDataOrFn(parentVal, childVal, vm)
    };

    /**
     * Hooks and props are merged as arrays.
     */
    function mergeHook (
        parentVal,
        childVal
    ) {
        return childVal
            ? parentVal
            ? parentVal.concat(childVal)
            : Array.isArray(childVal)
            ? childVal
            : [childVal]
            : parentVal
    }

    LIFECYCLE_HOOKS.forEach(function (hook) {
        strats[hook] = mergeHook;
    });

    /**
     * Assets
     *
     * When a vm is present (instance creation), we need to do
     * a three-way merge between constructor options, instance
     * options and parent options.
     */
    function mergeAssets (
        parentVal,
        childVal,
        vm,
        key
    ) {
        var res = Object.create(parentVal || null);
        if (childVal) {
            "development" !== 'production' && assertObjectType(key, childVal, vm);
            return extend(res, childVal)
        } else {
            return res
        }
    }

    ASSET_TYPES.forEach(function (type) {
        strats[type + 's'] = mergeAssets;
    });

    /**
     * Watchers.
     *
     * Watchers hashes should not overwrite one
     * another, so we merge them as arrays.
     */
    strats.watch = function (
        parentVal,
        childVal,
        vm,
        key
    ) {
        // work around Firefox's Object.prototype.watch...
        if (parentVal === nativeWatch) { parentVal = undefined; }
        if (childVal === nativeWatch) { childVal = undefined; }
        /* istanbul ignore if */
        if (!childVal) { return Object.create(parentVal || null) }
        {
            assertObjectType(key, childVal, vm);
        }
        if (!parentVal) { return childVal }
        var ret = {};
        extend(ret, parentVal);
        for (var key$1 in childVal) {
            var parent = ret[key$1];
            var child = childVal[key$1];
            if (parent && !Array.isArray(parent)) {
                parent = [parent];
            }
            ret[key$1] = parent
                ? parent.concat(child)
                : Array.isArray(child) ? child : [child];
        }
        return ret
    };

    /**
     * Other object hashes.
     */
    strats.props =
        strats.methods =
            strats.inject =
                strats.computed = function (
                    parentVal,
                    childVal,
                    vm,
                    key
                ) {
                    if (childVal && "development" !== 'production') {
                        assertObjectType(key, childVal, vm);
                    }
                    if (!parentVal) { return childVal }
                    var ret = Object.create(null);
                    extend(ret, parentVal);
                    if (childVal) { extend(ret, childVal); }
                    return ret
                };
    strats.provide = mergeDataOrFn;

    /**
     * Default strategy.
     */
    var defaultStrat = function (parentVal, childVal) {
        return childVal === undefined
            ? parentVal
            : childVal
    };

    /**
     * Validate component names
     */
    function checkComponents (options) {
        for (var key in options.components) {
            validateComponentName(key);
        }
    }

    function validateComponentName (name) {
        if (!/^[a-zA-Z][\w-]*$/.test(name)) {
            warn(
                'Invalid component name: "' + name + '". Component names ' +
                'can only contain alphanumeric characters and the hyphen, ' +
                'and must start with a letter.'
            );
        }
        if (isBuiltInTag(name) || config.isReservedTag(name)) {
            warn(
                'Do not use built-in or reserved HTML elements as component ' +
                'id: ' + name
            );
        }
    }

    /**
     * Ensure all props option syntax are normalized into the
     * Object-based format.
     */
    function normalizeProps (options, vm) {
        var props = options.props;
        if (!props) { return }
        var res = {};
        var i, val, name;
        if (Array.isArray(props)) {
            i = props.length;
            while (i--) {
                val = props[i];
                if (typeof val === 'string') {
                    name = camelize(val);
                    res[name] = { type: null };
                } else {
                    warn('props must be strings when using array syntax.');
                }
            }
        } else if (isPlainObject(props)) {
            for (var key in props) {
                val = props[key];
                name = camelize(key);
                res[name] = isPlainObject(val)
                    ? val
                    : { type: val };
            }
        } else {
            warn(
                "Invalid value for option \"props\": expected an Array or an Object, " +
                "but got " + (toRawType(props)) + ".",
                vm
            );
        }
        options.props = res;
    }

    /**
     * Normalize all injections into Object-based format
     */
    function normalizeInject (options, vm) {
        var inject = options.inject;
        if (!inject) { return }
        var normalized = options.inject = {};
        if (Array.isArray(inject)) {
            for (var i = 0; i < inject.length; i++) {
                normalized[inject[i]] = { from: inject[i] };
            }
        } else if (isPlainObject(inject)) {
            for (var key in inject) {
                var val = inject[key];
                normalized[key] = isPlainObject(val)
                    ? extend({ from: key }, val)
                    : { from: val };
            }
        } else {
            warn(
                "Invalid value for option \"inject\": expected an Array or an Object, " +
                "but got " + (toRawType(inject)) + ".",
                vm
            );
        }
    }

    /**
     * Normalize raw function directives into object format.
     */
    function normalizeDirectives (options) {
        var dirs = options.directives;
        if (dirs) {
            for (var key in dirs) {
                var def = dirs[key];
                if (typeof def === 'function') {
                    dirs[key] = { bind: def, update: def };
                }
            }
        }
    }

    function assertObjectType (name, value, vm) {
        if (!isPlainObject(value)) {
            warn(
                "Invalid value for option \"" + name + "\": expected an Object, " +
                "but got " + (toRawType(value)) + ".",
                vm
            );
        }
    }

    /**
     * Merge two option objects into a new one.
     * Core utility used in both instantiation and inheritance.
     */
    function mergeOptions (
        parent,
        child,
        vm
    ) {
        {
            checkComponents(child);
        }

        if (typeof child === 'function') {
            child = child.options;
        }

        normalizeProps(child, vm);
        normalizeInject(child, vm);
        normalizeDirectives(child);
        var extendsFrom = child.extends;
        if (extendsFrom) {
            parent = mergeOptions(parent, extendsFrom, vm);
        }
        if (child.mixins) {
            for (var i = 0, l = child.mixins.length; i < l; i++) {
                parent = mergeOptions(parent, child.mixins[i], vm);
            }
        }
        var options = {};
        var key;
        for (key in parent) {
            mergeField(key);
        }
        for (key in child) {
            if (!hasOwn(parent, key)) {
                mergeField(key);
            }
        }
        function mergeField (key) {
            var strat = strats[key] || defaultStrat;
            options[key] = strat(parent[key], child[key], vm, key);
        }
        return options
    }

    /**
     * Resolve an asset.
     * This function is used because child instances need access
     * to assets defined in its ancestor chain.
     */
    function resolveAsset (
        options,
        type,
        id,
        warnMissing
    ) {
        /* istanbul ignore if */
        if (typeof id !== 'string') {
            return
        }
        var assets = options[type];
        // check local registration variations first
        if (hasOwn(assets, id)) { return assets[id] }
        var camelizedId = camelize(id);
        if (hasOwn(assets, camelizedId)) { return assets[camelizedId] }
        var PascalCaseId = capitalize(camelizedId);
        if (hasOwn(assets, PascalCaseId)) { return assets[PascalCaseId] }
        // fallback to prototype chain
        var res = assets[id] || assets[camelizedId] || assets[PascalCaseId];
        if ("development" !== 'production' && warnMissing && !res) {
            warn(
                'Failed to resolve ' + type.slice(0, -1) + ': ' + id,
                options
            );
        }
        return res
    }

    /*  */

    function validateProp (
        key,
        propOptions,
        propsData,
        vm
    ) {
        var prop = propOptions[key];
        var absent = !hasOwn(propsData, key);
        var value = propsData[key];
        // boolean casting
        var booleanIndex = getTypeIndex(Boolean, prop.type);
        if (booleanIndex > -1) {
            if (absent && !hasOwn(prop, 'default')) {
                value = false;
            } else if (value === '' || value === hyphenate(key)) {
                // only cast empty string / same name to boolean if
                // boolean has higher priority
                var stringIndex = getTypeIndex(String, prop.type);
                if (stringIndex < 0 || booleanIndex < stringIndex) {
                    value = true;
                }
            }
        }
        // check default value
        if (value === undefined) {
            value = getPropDefaultValue(vm, prop, key);
            // since the default value is a fresh copy,
            // make sure to observe it.
            var prevShouldObserve = shouldObserve;
            toggleObserving(true);
            observe(value);
            toggleObserving(prevShouldObserve);
        }
        {
            assertProp(prop, key, value, vm, absent);
        }
        return value
    }

    /**
     * Get the default value of a prop.
     */
    function getPropDefaultValue (vm, prop, key) {
        // no default, return undefined
        if (!hasOwn(prop, 'default')) {
            return undefined
        }
        var def = prop.default;
        // warn against non-factory defaults for Object & Array
        if ("development" !== 'production' && isObject(def)) {
            warn(
                'Invalid default value for prop "' + key + '": ' +
                'Props with type Object/Array must use a factory function ' +
                'to return the default value.',
                vm
            );
        }
        // the raw prop value was also undefined from previous render,
        // return previous default value to avoid unnecessary watcher trigger
        if (vm && vm.$options.propsData &&
            vm.$options.propsData[key] === undefined &&
            vm._props[key] !== undefined
        ) {
            return vm._props[key]
        }
        // call factory function for non-Function types
        // a value is Function if its prototype is function even across different execution context
        return typeof def === 'function' && getType(prop.type) !== 'Function'
            ? def.call(vm)
            : def
    }

    /**
     * Assert whether a prop is valid.
     */
    function assertProp (
        prop,
        name,
        value,
        vm,
        absent
    ) {
        if (prop.required && absent) {
            warn(
                'Missing required prop: "' + name + '"',
                vm
            );
            return
        }
        if (value == null && !prop.required) {
            return
        }
        var type = prop.type;
        var valid = !type || type === true;
        var expectedTypes = [];
        if (type) {
            if (!Array.isArray(type)) {
                type = [type];
            }
            for (var i = 0; i < type.length && !valid; i++) {
                var assertedType = assertType(value, type[i]);
                expectedTypes.push(assertedType.expectedType || '');
                valid = assertedType.valid;
            }
        }
        if (!valid) {
            warn(
                "Invalid prop: type check failed for prop \"" + name + "\"." +
                " Expected " + (expectedTypes.map(capitalize).join(', ')) +
                ", got " + (toRawType(value)) + ".",
                vm
            );
            return
        }
        var validator = prop.validator;
        if (validator) {
            if (!validator(value)) {
                warn(
                    'Invalid prop: custom validator check failed for prop "' + name + '".',
                    vm
                );
            }
        }
    }

    var simpleCheckRE = /^(String|Number|Boolean|Function|Symbol)$/;

    function assertType (value, type) {
        var valid;
        var expectedType = getType(type);
        if (simpleCheckRE.test(expectedType)) {
            var t = typeof value;
            valid = t === expectedType.toLowerCase();
            // for primitive wrapper objects
            if (!valid && t === 'object') {
                valid = value instanceof type;
            }
        } else if (expectedType === 'Object') {
            valid = isPlainObject(value);
        } else if (expectedType === 'Array') {
            valid = Array.isArray(value);
        } else {
            valid = value instanceof type;
        }
        return {
            valid: valid,
            expectedType: expectedType
        }
    }

    /**
     * Use function string name to check built-in types,
     * because a simple equality check will fail when running
     * across different vms / iframes.
     */
    function getType (fn) {
        var match = fn && fn.toString().match(/^\s*function (\w+)/);
        return match ? match[1] : ''
    }

    function isSameType (a, b) {
        return getType(a) === getType(b)
    }

    function getTypeIndex (type, expectedTypes) {
        if (!Array.isArray(expectedTypes)) {
            return isSameType(expectedTypes, type) ? 0 : -1
        }
        for (var i = 0, len = expectedTypes.length; i < len; i++) {
            if (isSameType(expectedTypes[i], type)) {
                return i
            }
        }
        return -1
    }

    /*  */

    function handleError (err, vm, info) {
        if (vm) {
            var cur = vm;
            while ((cur = cur.$parent)) {
                var hooks = cur.$options.errorCaptured;
                if (hooks) {
                    for (var i = 0; i < hooks.length; i++) {
                        try {
                            var capture = hooks[i].call(cur, err, vm, info) === false;
                            if (capture) { return }
                        } catch (e) {
                            globalHandleError(e, cur, 'errorCaptured hook');
                        }
                    }
                }
            }
        }
        globalHandleError(err, vm, info);
    }

    function globalHandleError (err, vm, info) {
        if (config.errorHandler) {
            try {
                return config.errorHandler.call(null, err, vm, info)
            } catch (e) {
                logError(e, null, 'config.errorHandler');
            }
        }
        logError(err, vm, info);
    }

    function logError (err, vm, info) {
        {
            warn(("Error in " + info + ": \"" + (err.toString()) + "\""), vm);
        }
        /* istanbul ignore else */
        if ((inBrowser || inWeex) && typeof console !== 'undefined') {
            console.error(err);
        } else {
            throw err
        }
    }

    /*  */
    /* globals MessageChannel */

    var callbacks = [];
    var pending = false;

    function flushCallbacks () {
        pending = false;
        var copies = callbacks.slice(0);
        callbacks.length = 0;
        for (var i = 0; i < copies.length; i++) {
            copies[i]();
        }
    }

// Here we have async deferring wrappers using both microtasks and (macro) tasks.
// In < 2.4 we used microtasks everywhere, but there are some scenarios where
// microtasks have too high a priority and fire in between supposedly
// sequential events (e.g. #4521, #6690) or even between bubbling of the same
// event (#6566). However, using (macro) tasks everywhere also has subtle problems
// when state is changed right before repaint (e.g. #6813, out-in transitions).
// Here we use microtask by default, but expose a way to force (macro) task when
// needed (e.g. in event handlers attached by v-on).
    var microTimerFunc;
    var macroTimerFunc;
    var useMacroTask = false;

// Determine (macro) task defer implementation.
// Technically setImmediate should be the ideal choice, but it's only available
// in IE. The only polyfill that consistently queues the callback after all DOM
// events triggered in the same loop is by using MessageChannel.
    /* istanbul ignore if */
    if (typeof setImmediate !== 'undefined' && isNative(setImmediate)) {
        macroTimerFunc = function () {
            setImmediate(flushCallbacks);
        };
    } else if (typeof MessageChannel !== 'undefined' && (
            isNative(MessageChannel) ||
            // PhantomJS
            MessageChannel.toString() === '[object MessageChannelConstructor]'
        )) {
        var channel = new MessageChannel();
        var port = channel.port2;
        channel.port1.onmessage = flushCallbacks;
        macroTimerFunc = function () {
            port.postMessage(1);
        };
    } else {
        /* istanbul ignore next */
        macroTimerFunc = function () {
            setTimeout(flushCallbacks, 0);
        };
    }

// Determine microtask defer implementation.
    /* istanbul ignore next, $flow-disable-line */
    if (typeof Promise !== 'undefined' && isNative(Promise)) {
        var p = Promise.resolve();
        microTimerFunc = function () {
            p.then(flushCallbacks);
            // in problematic UIWebViews, Promise.then doesn't completely break, but
            // it can get stuck in a weird state where callbacks are pushed into the
            // microtask queue but the queue isn't being flushed, until the browser
            // needs to do some other work, e.g. handle a timer. Therefore we can
            // "force" the microtask queue to be flushed by adding an empty timer.
            if (isIOS) { setTimeout(noop); }
        };
    } else {
        // fallback to macro
        microTimerFunc = macroTimerFunc;
    }

    /**
     * Wrap a function so that if any code inside triggers state change,
     * the changes are queued using a (macro) task instead of a microtask.
     */
    function withMacroTask (fn) {
        return fn._withTask || (fn._withTask = function () {
                useMacroTask = true;
                var res = fn.apply(null, arguments);
                useMacroTask = false;
                return res
            })
    }

    function nextTick (cb, ctx) {
        var _resolve;
        callbacks.push(function () {
            if (cb) {
                try {
                    cb.call(ctx);
                } catch (e) {
                    handleError(e, ctx, 'nextTick');
                }
            } else if (_resolve) {
                _resolve(ctx);
            }
        });
        if (!pending) {
            pending = true;
            if (useMacroTask) {
                macroTimerFunc();
            } else {
                microTimerFunc();
            }
        }
        // $flow-disable-line
        if (!cb && typeof Promise !== 'undefined') {
            return new Promise(function (resolve) {
                _resolve = resolve;
            })
        }
    }

    /*  */

    var mark;
    var measure;

    {
        var perf = inBrowser && window.performance;
        /* istanbul ignore if */
        if (
            perf &&
            perf.mark &&
            perf.measure &&
            perf.clearMarks &&
            perf.clearMeasures
        ) {
            mark = function (tag) { return perf.mark(tag); };
            measure = function (name, startTag, endTag) {
                perf.measure(name, startTag, endTag);
                perf.clearMarks(startTag);
                perf.clearMarks(endTag);
                perf.clearMeasures(name);
            };
        }
    }

    /* not type checking this file because flow doesn't play well with Proxy */

    var initProxy;

    {
        var allowedGlobals = makeMap(
            'Infinity,undefined,NaN,isFinite,isNaN,' +
            'parseFloat,parseInt,decodeURI,decodeURIComponent,encodeURI,encodeURIComponent,' +
            'Math,Number,Date,Array,Object,Boolean,String,RegExp,Map,Set,JSON,Intl,' +
            'require' // for Webpack/Browserify
        );

        var warnNonPresent = function (target, key) {
            warn(
                "Property or method \"" + key + "\" is not defined on the instance but " +
                'referenced during render. Make sure that this property is reactive, ' +
                'either in the data option, or for class-based components, by ' +
                'initializing the property. ' +
                'See: https://vuejs.org/v2/guide/reactivity.html#Declaring-Reactive-Properties.',
                target
            );
        };

        var hasProxy =
            typeof Proxy !== 'undefined' && isNative(Proxy);

        if (hasProxy) {
            var isBuiltInModifier = makeMap('stop,prevent,self,ctrl,shift,alt,meta,exact');
            config.keyCodes = new Proxy(config.keyCodes, {
                set: function set (target, key, value) {
                    if (isBuiltInModifier(key)) {
                        warn(("Avoid overwriting built-in modifier in config.keyCodes: ." + key));
                        return false
                    } else {
                        target[key] = value;
                        return true
                    }
                }
            });
        }

        var hasHandler = {
            has: function has (target, key) {
                var has = key in target;
                var isAllowed = allowedGlobals(key) || key.charAt(0) === '_';
                if (!has && !isAllowed) {
                    warnNonPresent(target, key);
                }
                return has || !isAllowed
            }
        };

        var getHandler = {
            get: function get (target, key) {
                if (typeof key === 'string' && !(key in target)) {
                    warnNonPresent(target, key);
                }
                return target[key]
            }
        };

        initProxy = function initProxy (vm) {
            if (hasProxy) {
                // determine which proxy handler to use
                var options = vm.$options;
                var handlers = options.render && options.render._withStripped
                    ? getHandler
                    : hasHandler;
                vm._renderProxy = new Proxy(vm, handlers);
            } else {
                vm._renderProxy = vm;
            }
        };
    }

    /*  */

    var seenObjects = new _Set();

    /**
     * Recursively traverse an object to evoke all converted
     * getters, so that every nested property inside the object
     * is collected as a "deep" dependency.
     */
    function traverse (val) {
        _traverse(val, seenObjects);
        seenObjects.clear();
    }

    function _traverse (val, seen) {
        var i, keys;
        var isA = Array.isArray(val);
        if ((!isA && !isObject(val)) || Object.isFrozen(val) || val instanceof VNode) {
            return
        }
        if (val.__ob__) {
            var depId = val.__ob__.dep.id;
            if (seen.has(depId)) {
                return
            }
            seen.add(depId);
        }
        if (isA) {
            i = val.length;
            while (i--) { _traverse(val[i], seen); }
        } else {
            keys = Object.keys(val);
            i = keys.length;
            while (i--) { _traverse(val[keys[i]], seen); }
        }
    }

    /*  */

    var normalizeEvent = cached(function (name) {
        var passive = name.charAt(0) === '&';
        name = passive ? name.slice(1) : name;
        var once$$1 = name.charAt(0) === '~'; // Prefixed last, checked first
        name = once$$1 ? name.slice(1) : name;
        var capture = name.charAt(0) === '!';
        name = capture ? name.slice(1) : name;
        return {
            name: name,
            once: once$$1,
            capture: capture,
            passive: passive
        }
    });

    function createFnInvoker (fns) {
        function invoker () {
            var arguments$1 = arguments;

            var fns = invoker.fns;
            if (Array.isArray(fns)) {
                var cloned = fns.slice();
                for (var i = 0; i < cloned.length; i++) {
                    cloned[i].apply(null, arguments$1);
                }
            } else {
                // return handler return value for single handlers
                return fns.apply(null, arguments)
            }
        }
        invoker.fns = fns;
        return invoker
    }

    function updateListeners (
        on,
        oldOn,
        add,
        remove$$1,
        vm
    ) {
        var name, def, cur, old, event;
        for (name in on) {
            def = cur = on[name];
            old = oldOn[name];
            event = normalizeEvent(name);
            /* istanbul ignore if */
            if (isUndef(cur)) {
                "development" !== 'production' && warn(
                    "Invalid handler for event \"" + (event.name) + "\": got " + String(cur),
                    vm
                );
            } else if (isUndef(old)) {
                if (isUndef(cur.fns)) {
                    cur = on[name] = createFnInvoker(cur);
                }
                add(event.name, cur, event.once, event.capture, event.passive, event.params);
            } else if (cur !== old) {
                old.fns = cur;
                on[name] = old;
            }
        }
        for (name in oldOn) {
            if (isUndef(on[name])) {
                event = normalizeEvent(name);
                remove$$1(event.name, oldOn[name], event.capture);
            }
        }
    }

    /*  */

    function mergeVNodeHook (def, hookKey, hook) {
        if (def instanceof VNode) {
            def = def.data.hook || (def.data.hook = {});
        }
        var invoker;
        var oldHook = def[hookKey];

        function wrappedHook () {
            hook.apply(this, arguments);
            // important: remove merged hook to ensure it's called only once
            // and prevent memory leak
            remove(invoker.fns, wrappedHook);
        }

        if (isUndef(oldHook)) {
            // no existing hook
            invoker = createFnInvoker([wrappedHook]);
        } else {
            /* istanbul ignore if */
            if (isDef(oldHook.fns) && isTrue(oldHook.merged)) {
                // already a merged invoker
                invoker = oldHook;
                invoker.fns.push(wrappedHook);
            } else {
                // existing plain hook
                invoker = createFnInvoker([oldHook, wrappedHook]);
            }
        }

        invoker.merged = true;
        def[hookKey] = invoker;
    }

    /*  */

    function extractPropsFromVNodeData (
        data,
        Ctor,
        tag
    ) {
        // we are only extracting raw values here.
        // validation and default values are handled in the child
        // component itself.
        var propOptions = Ctor.options.props;
        if (isUndef(propOptions)) {
            return
        }
        var res = {};
        var attrs = data.attrs;
        var props = data.props;
        if (isDef(attrs) || isDef(props)) {
            for (var key in propOptions) {
                var altKey = hyphenate(key);
                {
                    var keyInLowerCase = key.toLowerCase();
                    if (
                        key !== keyInLowerCase &&
                        attrs && hasOwn(attrs, keyInLowerCase)
                    ) {
                        tip(
                            "Prop \"" + keyInLowerCase + "\" is passed to component " +
                            (formatComponentName(tag || Ctor)) + ", but the declared prop name is" +
                            " \"" + key + "\". " +
                            "Note that HTML attributes are case-insensitive and camelCased " +
                            "props need to use their kebab-case equivalents when using in-DOM " +
                            "templates. You should probably use \"" + altKey + "\" instead of \"" + key + "\"."
                        );
                    }
                }
                checkProp(res, props, key, altKey, true) ||
                checkProp(res, attrs, key, altKey, false);
            }
        }
        return res
    }

    function checkProp (
        res,
        hash,
        key,
        altKey,
        preserve
    ) {
        if (isDef(hash)) {
            if (hasOwn(hash, key)) {
                res[key] = hash[key];
                if (!preserve) {
                    delete hash[key];
                }
                return true
            } else if (hasOwn(hash, altKey)) {
                res[key] = hash[altKey];
                if (!preserve) {
                    delete hash[altKey];
                }
                return true
            }
        }
        return false
    }

    /*  */

// The template compiler attempts to minimize the need for normalization by
// statically analyzing the template at compile time.
//
// For plain HTML markup, normalization can be completely skipped because the
// generated render function is guaranteed to return Array. There are
// two cases where extra normalization is needed:

// 1. When the children contains components - because a functional component
// may return an Array instead of a single root. In this case, just a simple
// normalization is needed - if any child is an Array, we flatten the whole
// thing with Array.prototype.concat. It is guaranteed to be only 1-level deep
// because functional components already normalize their own children.
    function simpleNormalizeChildren (children) {
        for (var i = 0; i < children.length; i++) {
            if (Array.isArray(children[i])) {
                return Array.prototype.concat.apply([], children)
            }
        }
        return children
    }

// 2. When the children contains constructs that always generated nested Arrays,
// e.g.