// initGlobalAPI
Vue.config
Vue.util = {
    warn,
    extend,
    mergeOptions,
    defineReactive
}
Vue.set = set
Vue.delete = del
Vue.nextTick = nextTick
Vue.options = {
    components: {
        KeepAlive
        // Transition 和 TransitionGroup 組件在 runtime/index.js 文件中被添加
        // Transition,
        // TransitionGroup
    },
    directives: Object.create(null),
    // 在 runtime/index.js 文件中，為 directives 添加了兩個平臺化的指令 model 和 show
    // directives:{
    //  model,
    //  show
    // },
    filters: Object.create(null),
    _base: Vue
}

// initUse ***************** global-api/use.js
Vue.use = function (plugin: Function | Object) {}

// initMixin ***************** global-api/mixin.js
Vue.mixin = function (mixin: Object) {}

// initExtend ***************** global-api/extend.js
Vue.cid = 0
Vue.extend = function (extendOptions: Object): Function {}

// initAssetRegisters ***************** global-api/assets.js
Vue.component =
Vue.directive =
Vue.filter = function (
  id: string,
  definition: Function | Object
): Function | Object | void {}

// expose FunctionalRenderContext for ssr runtime helper installation
Object.defineProperty(Vue, 'FunctionalRenderContext', {
  value: FunctionalRenderContext
})

Vue.version = '__VERSION__'

// entry-runtime-with-compiler.js
Vue.compile = compileToFunctions