/*! * Vue.js v2.6.10 * (c) 2014-2019 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 = global || self, global.Vue = factory()); }(this, function () { 'use strict'; /* */ var emptyObject = Object.freeze({}); // These helpers produce 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) } function isPromise (val) { return ( isDef(val) && typeof val.then === 'function' && typeof val.catch === 'function' ) } /** * Convert a value to a string that is actually rendered. */ function toString (val) { return val == null ? '' : Array.isArray(val) || (isPlainObject(val) && val.toString === _toString) ? JSON.stringify(val, null, 2) : String(val) } /** * Convert an 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 an 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 an 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 performant enough in most browsers. * But removing it would mean breaking code that was able to run in * PhantomJS 1.x, so this must be kept for backward 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 } /* eslint-disable no-unused-vars */ /** * 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; }; /* eslint-enable no-unused-vars */ /** * Return the same value. */ var identity = function (_) { return _; }; /** * Generate a string containing static keys 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 (a instanceof Date && b instanceof Date) { return a.getTime() === b.getTime() } 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 } } /** * Return the first index at which a loosely equal value can be * found in the array (if value is a plain object, the array must * contain an object of the same shape), or -1 if it is not present. */ 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', 'serverPrefetch' ]; /* */ 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, /** * Perform updates asynchronously. Intended to be used by Vue Test Utils * This will significantly reduce performance if set to false. */ async: true, /** * Exposed for legacy reasons */ _lifecycleHooks: LIFECYCLE_HOOKS }); /* */ /** * unicode letters used for parsing html tags, component names and property paths. * using https://www.w3.org/TR/html53/semantics-scripting.html#potentialcustomelementname * skipping \u10000-\uEFFFF due to it freezing up PhantomJS */ var unicodeRegExp = /a-zA-Z\u00B7\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u037D\u037F-\u1FFF\u200C-\u200D\u203F-\u2040\u2070-\u218F\u2C00-\u2FEF\u3001-\uD7FF\uF900-\uFDCF\uFDF0-\uFFFD/; /** * 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 = new RegExp(("[^" + (unicodeRegExp.source) + ".$_\\d]")); 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('index-6.html') > 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; var isPhantomJS = UA && /phantomjs/.test(UA); var isFF = UA && UA.match(/firefox\/(\d+)/); // 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'] && 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 */ // $flow-disable-line if (typeof Set !== 'undefined' && isNative(Set)) { // use native Set when available. _Set = Set; } else { // a non-standard Set polyfill that only works with primitive keys. _Set = /*@__PURE__*/(function () { function Set () { this.set = Object.create(null); } Set.prototype.has = function has (key) { return this.set[key] === true }; Set.prototype.add = function add (key) { this.set[key] = true; }; Set.prototype.clear = function clear () { this.set = Object.create(null); }; return Set; }()); } /* */ var warn = noop; var tip = noop; var generateComponentTrace = (noop); // work around flow check var formatComponentName = (noop); { var hasConsole = typeof console !== 'undefined'; var classifyRE = /(?:^|[-_])(\w)/g; var classify = function (str) { return str .replace(classifyRE, function (c) { return c.toUpperCase(); }) .replace(/[-_]/g, ''); }; warn = function (msg, vm) { var trace = vm ? generateComponentTrace(vm) : ''; if (config.warnHandler) { config.warnHandler.call(null, msg, vm, trace); } else if (hasConsole && (!config.silent)) { console.error(("[Vue warn]: " + msg + trace)); } }; tip = function (msg, vm) { if (hasConsole && (!config.silent)) { console.warn("[Vue tip]: " + msg + ( vm ? generateComponentTrace(vm) : '' )); } }; formatComponentName = function (vm, includeFile) { if (vm.$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(); if (!config.async) { // subs aren't sorted in scheduler if not running async // we need to sort them now to make sure they fire in correct // order subs.sort(function (a, b) { return a.id - b.id; }); } for (var i = 0, l = subs.length; i < l; i++) { subs[i].update(); } }; // The current target watcher being evaluated. // This is globally unique because only one watcher // can be evaluated at a time. Dep.target = null; var targetStack = []; function pushTarget (target) { targetStack.push(target); Dep.target = target; } function popTarget () { targetStack.pop(); Dep.target = targetStack[targetStack.length - 1]; } /* */ 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, // #7975 // clone children array to avoid mutating original in case of cloning // a child. vnode.children && vnode.children.slice(), 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.asyncMeta = vnode.asyncMeta; 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)) { if (hasProto) { protoAugment(value, arrayMethods); } else { copyAugment(value, arrayMethods, arrayKeys); } this.observeArray(value); } else { this.walk(value); } }; /** * Walk through all properties 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$$1(obj, keys[i]); } }; /** * Observe a list of Array items. */ Observer.prototype.observeArray = function observeArray (items) { for (var i = 0, l = items.length; i < l; i++) { observe(items[i]); } }; // helpers /** * Augment a target Object or Array by intercepting * the prototype chain using __proto__ */ function protoAugment (target, src) { /* eslint-disable no-proto */ target.__proto__ = src; /* eslint-enable no-proto */ } /** * Augment a target Object or Array by defining * hidden properties. */ /* istanbul ignore next */ function copyAugment (target, src, keys) { for (var i = 0, l = keys.length; i < l; i++) { var key = keys[i]; def(target, key, src[key]); } } /** * Attempt to create an observer instance for a value, * returns the new observer if successfully observed, * or the existing observer if the value already has one. */ function observe (value, asRootData) { if (!isObject(value) || value instanceof VNode) { return } var ob; if (hasOwn(value, '__ob__') && value.__ob__ instanceof Observer) { ob = value.__ob__; } else if ( shouldObserve && !isServerRendering() && (Array.isArray(value) || isPlainObject(value)) && Object.isExtensible(value) && !value._isVue ) { ob = new Observer(value); } if (asRootData && ob) { ob.vmCount++; } return ob } /** * Define a reactive property on an Object. */ function defineReactive$$1 ( 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; var setter = property && property.set; if ((!getter || setter) && arguments.length === 2) { val = obj[key]; } 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 (customSetter) { customSetter(); } // #7981: for accessor properties without setter if (getter && !setter) { return } 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 (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)) { 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$$1(ob.value, key, val); ob.dep.notify(); return val } /** * Delete a property and trigger change if necessary. */ function del (target, key) { if (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)) { 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 = hasSymbol ? Reflect.ownKeys(from) : Object.keys(from); for (var i = 0; i < keys.length; i++) { key = keys[i]; // in case the object is already observed... if (key === '__ob__') { continue } toVal = to[key]; fromVal = from[key]; if (!hasOwn(to, key)) { set(to, key, fromVal); } else if ( toVal !== fromVal && 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') { 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 ) { var res = childVal ? parentVal ? parentVal.concat(childVal) : Array.isArray(childVal) ? childVal : [childVal] : parentVal; return res ? dedupeHooks(res) : res } function dedupeHooks (hooks) { var res = []; for (var i = 0; i < hooks.length; i++) { if (res.indexOf(hooks[i]) === -1) { res.push(hooks[i]); } } return res } 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) { 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 (!new RegExp(("^[a-zA-Z][\\-\\.0-9_" + (unicodeRegExp.source) + "]*$")).test(name)) { warn( 'Invalid component name: "' + name + '". Component names ' + 'should conform to valid custom element name in html5 specification.' ); } 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$$1 = dirs[key]; if (typeof def$$1 === 'function') { dirs[key] = { bind: def$$1, update: def$$1 }; } } } } 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); // Apply extends and mixins on the child options, // but only if it is a raw options object that isn't // the result of another mergeOptions call. // Only merged options has the _base property. if (!child._base) { if (child.extends) { parent = mergeOptions(parent, child.extends, 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 (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 (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( getInvalidTypeMessage(name, value, expectedTypes), 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 getInvalidTypeMessage (name, value, expectedTypes) { var message = "Invalid prop: type check failed for prop \"" + name + "\"." + " Expected " + (expectedTypes.map(capitalize).join(', ')); var expectedType = expectedTypes[0]; var receivedType = toRawType(value); var expectedValue = styleValue(value, expectedType); var receivedValue = styleValue(value, receivedType); // check if we need to specify expected value if (expectedTypes.length === 1 && isExplicable(expectedType) && !isBoolean(expectedType, receivedType)) { message += " with value " + expectedValue; } message += ", got " + receivedType + " "; // check if we need to specify received value if (isExplicable(receivedType)) { message += "with value " + receivedValue + "."; } return message } function styleValue (value, type) { if (type === 'String') { return ("\"" + value + "\"") } else if (type === 'Number') { return ("" + (Number(value))) } else { return ("" + value) } } function isExplicable (value) { var explicitTypes = ['string', 'number', 'boolean']; return explicitTypes.some(function (elem) { return value.toLowerCase() === elem; }) } function isBoolean () { var args = [], len = arguments.length; while ( len-- ) args[ len ] = arguments[ len ]; return args.some(function (elem) { return elem.toLowerCase() === 'boolean'; }) } /* */ function handleError (err, vm, info) { // Deactivate deps tracking while processing error handler to avoid possible infinite rendering. // See: https://github.com/vuejs/vuex/issues/1505 pushTarget(); try { 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); } finally { popTarget(); } } function invokeWithErrorHandling ( handler, context, args, vm, info ) { var res; try { res = args ? handler.apply(context, args) : handler.call(context); if (res && !res._isVue && isPromise(res) && !res._handled) { res.catch(function (e) { return handleError(e, vm, info + " (Promise/async)"); }); // issue #9511 // avoid catch triggering multiple times when nested calls res._handled = true; } } catch (e) { handleError(e, vm, info); } return res } function globalHandleError (err, vm, info) { if (config.errorHandler) { try { return config.errorHandler.call(null, err, vm, info) } catch (e) { // if the user intentionally throws the original error in the handler, // do not log it twice if (e !== err) { 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 } } /* */ var isUsingMicroTask = false; 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 microtasks. // In 2.5 we used (macro) tasks (in combination with microtasks). // However, it has subtle problems when state is changed right before repaint // (e.g. #6813, out-in transitions). // Also, using (macro) tasks in event handler would cause some weird behaviors // that cannot be circumvented (e.g. #7109, #7153, #7546, #7834, #8109). // So we now use microtasks everywhere, again. // A major drawback of this tradeoff is that there are some scenarios // where microtasks have too high a priority and fire in between supposedly // sequential events (e.g. #4521, #6690, which have workarounds) // or even between bubbling of the same event (#6566). var timerFunc; // The nextTick behavior leverages the microtask queue, which can be accessed // via either native Promise.then or MutationObserver. // MutationObserver has wider support, however it is seriously bugged in // UIWebView in iOS >= 9.3.3 when triggered in touch event handlers. It // completely stops working after triggering a few times... so, if native // Promise is available, we will use it: /* istanbul ignore next, $flow-disable-line */ if (typeof Promise !== 'undefined' && isNative(Promise)) { var p = Promise.resolve(); timerFunc = 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); } }; isUsingMicroTask = true; } else if (!isIE && typeof MutationObserver !== 'undefined' && ( isNative(MutationObserver) || // PhantomJS and iOS 7.x MutationObserver.toString() === '[object MutationObserverConstructor]' )) { // Use MutationObserver where native Promise is not available, // e.g. PhantomJS, iOS7, Android 4.4 // (#6466 MutationObserver is unreliable in IE11) var counter = 1; var observer = new MutationObserver(flushCallbacks); var textNode = document.createTextNode(String(counter)); observer.observe(textNode, { characterData: true }); timerFunc = function () { counter = (counter + 1) % 2; textNode.data = String(counter); }; isUsingMicroTask = true; } else if (typeof setImmediate !== 'undefined' && isNative(setImmediate)) { // Fallback to setImmediate. // Techinically it leverages the (macro) task queue, // but it is still a better choice than setTimeout. timerFunc = function () { setImmediate(flushCallbacks); }; } else { // Fallback to setTimeout. timerFunc = function () { setTimeout(flushCallbacks, 0); }; } 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; timerFunc(); } // $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 warnReservedPrefix = function (target, key) { warn( "Property \"" + key + "\" must be accessed with \"$data." + key + "\" because " + 'properties starting with "$" or "_" are not proxied in the Vue instance to ' + 'prevent conflicts with Vue internals' + 'See: https://vuejs.org/v2/api/#data', 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) || (typeof key === 'string' && key.charAt(0) === '_' && !(key in target.$data)); if (!has && !isAllowed) { if (key in target.$data) { warnReservedPrefix(target, key); } else { warnNonPresent(target, key); } } return has || !isAllowed } }; var getHandler = { get: function get (target, key) { if (typeof key === 'string' && !(key in target)) { if (key in target.$data) { warnReservedPrefix(target, key); } else { 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, vm) { 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++) { invokeWithErrorHandling(cloned[i], null, arguments$1, vm, "v-on handler"); } } else { // return handler return value for single handlers return invokeWithErrorHandling(fns, null, arguments, vm, "v-on handler") } } invoker.fns = fns; return invoker } function updateListeners ( on, oldOn, add, remove$$1, createOnceHandler, vm ) { var name, def$$1, cur, old, event; for (name in on) { def$$1 = cur = on[name]; old = oldOn[name]; event = normalizeEvent(name); if (isUndef(cur)) { warn( "Invalid handler for event \"" + (event.name) + "\": got " + String(cur), vm ); } else if (isUndef(old)) { if (isUndef(cur.fns)) { cur = on[name] = createFnInvoker(cur, vm); } if (isTrue(event.once)) { cur = on[name] = createOnceHandler(event.name, cur, event.capture); } add(event.name, cur, event.capture, event.passive, event.params); } else if (cur !== old) { old.fns = cur; on[name] = old; } } for (name in oldOn) { if (isUndef(on[name])) { event = normalizeEvent(name); remove$$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.