import config from './config'
//加载初始全局API
import { initGlobalAPI } from './global-api/index'
//类的初始化入口
import Vue from './instance/index'

initGlobalAPI(Vue)
//在Vue类的原型上定义$isServer属性，用于判断是否支持服务端渲染
//这样在Vue实例上调用vue.$isServer就可以知道是否开启了SSR
//关于Object.defineProperty，这是一个ES5的方法，可以直接在对象上定义属性
//Vue的数据绑定机制就是用的Object.defineProperty，这也是Vue不支持IE8及以下版本的原因
//将data对象的属性转成getter和setter，具体原理见http://cn.vuejs.org/guide/reactivity.html
Object.defineProperty(Vue.prototype, '$isServer', {
  get: () => config._isServer
})
//定义Vue版本号
Vue.version = '2.0.0-rc.4'

export default Vue

//Vue使用了Flow做静态类型检查
//Flow可以在代码运行前检查出参数、返回值、变量等类型异常
//方便我们在代码运行前进行部分debug
/* @flow */
import { no, noop } from 'shared/util'
export type Config = {
  optionMergeStrategies: { [key: string]: Function };
  silent: boolean;
  devtools: boolean;
  errorHandler: ?Function;
  ignoredElements: ?Array<string>;
  keyCodes: { [key: string]: number };
  // platform
  isReservedTag: (x?: string) => boolean;
  isUnknownElement: (x?: string) => boolean;
  getTagNamespace: (x?: string) => string | void;
  mustUseProp: (x?: string) => boolean;
  // internal
  _assetTypes: Array<string>;
  _lifecycleHooks: Array<string>;
  _maxUpdateCount: number;
  _isServer: boolean;
}
const config: Config = {
  optionMergeStrategies: Object.create(null),
  //是否显示warning,默认显示
  silent: false,
  //是否启动devtool
  devtools: process.env.NODE_ENV !== 'production',
  errorHandler: null,
  ignoredElements: null,
  keyCodes: Object.create(null),
  isReservedTag: no,
  isUnknownElement: no,
  getTagNamespace: noop,
  mustUseProp: no,
 //组件的默认类型
  _assetTypes: [
    'component',
    'directive',
    'filter'
  ],
 //定义组件的各种生命周期
  _lifecycleHooks: [
    'beforeCreate',
    'created',
    'beforeMount',
    'mounted',
    'beforeUpdate',
    'updated',
    'beforeDestroy',
    'destroyed',
    'activated',
    'deactivated'
  ],
 //规定组件在一次刷新中的最大循环更新次数
  _maxUpdateCount: 100,
  //判断全局环境是否为server
  _isServer: process.env.VUE_ENV === 'server'
}
export default config

import { initMixin } from './init'
import { stateMixin } from './state'
import { renderMixin } from './render'
import { eventsMixin } from './events'
import { lifecycleMixin } from './lifecycle'

function Vue (options) {
  this._init(options)
}

initMixin(Vue)
stateMixin(Vue)
eventsMixin(Vue)
lifecycleMixin(Vue)
renderMixin(Vue)

export default Vue

//为了说明，这里是其简化版
export function eventsMixin (Vue: Class<Component>) {
  //实现事件绑定的方法，将其添加到原型上
  Vue.prototype.$on = function (event: string, fn: Function): Component {
    const vm: Component = this
   //支持绑定多个事件
    ;(vm._events[event] || (vm._events[event] = [])).push(fn)
    return vm
  }