古灬风

vue.js源码

/*!
* Vue.js v2.5.21
* (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 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)
}

/**
* 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 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'
];

/* */

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
});

/* */

/**
* 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;

// 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 there could be only one
// watcher being evaluated at any 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];
}

/**
* 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 = 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 (
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
) {
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) {
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);

// 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);
}
}
}

/**
* 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
}

/* */

/**
* 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)$/;

/**
* 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 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 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
}
}

/* */

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;
try {
return fn.apply(null, arguments)
} finally {
useMacroTask = false;
}
})
}

/* */

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
}
}
});
}

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();
}

/* */

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;

/* */

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;
}

/* */

/* */

// 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.