Vue2.0源码思维导图-------------Vue 初始化

上一节看完《Vue源码思维导图-------------Vue 构造函数、原型、静态属性和方法》，这节将会以new Vue()为入口，大体看下 this._init()要做的事情。

 function Vue (options) {
   if (process.env.NODE_ENV !== 'production' &&
     !(this instanceof Vue)
   ) {
     warn('Vue is a constructor and should be called with the `new` keyword')
   }
   this._init(options)
 }

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

 export default Vue

下边解开_init的面纱

 export function initMixin (Vue: Class<Component>) {
   Vue.prototype._init = function (options?: Object) {
     const vm: Component = this
     // a uid
     vm._uid = uid++

     let startTag, endTag
     /* istanbul ignore if */
     if (process.env.NODE_ENV !== 'production' && config.performance && mark) {
       startTag = `vue-perf-start:${vm._uid}`
       endTag = `vue-perf-end:${vm._uid}`
       mark(startTag)
     }

     // a flag to avoid this being observed
     vm._isVue = true
     // merge options
     if (options && options._isComponent) {
       // optimize internal component instantiation
       // since dynamic options merging is pretty slow, and none of the
       // internal component options needs special treatment.
       initInternalComponent(vm, options)
     } else {
       vm.$options = mergeOptions(
         resolveConstructorOptions(vm.constructor),
         options || {},
         vm
       )
     }
     /* istanbul ignore else */
     if (process.env.NODE_ENV !== 'production') {
       initProxy(vm)
     } else {
       vm._renderProxy = vm
     }
     // expose real self
     vm._self = vm
     initLifecycle(vm)
     initEvents(vm)
     initRender(vm)
     callHook(vm, 'beforeCreate')
     initInjections(vm) // resolve injections before data/props
     initState(vm)
     initProvide(vm) // resolve provide after data/props
     callHook(vm, 'created')

     /* istanbul ignore if */
     if (process.env.NODE_ENV !== 'production' && config.performance && mark) {
       vm._name = formatComponentName(vm, false)
       mark(endTag)
       measure(`vue ${vm._name} init`, startTag, endTag)
     }

     if (vm.$options.el) {
       vm.$mount(vm.$options.el)
     }
   }
 }

总结思维导图如下：

高清原图地址：https://github.com/huashuaipeng/vue--/blob/master/Vue_init.png

// Vue.prototype._init
vm._uid = uid++     // 每个Vue实例都拥有一个唯一的 id
vm._isVue = true    // 这个表示用于避免Vue实例对象被观测(observed)
vm.$options         // 当前 Vue 实例的初始化选项，注意：这是经过 mergeOptions() 后的
vm._renderProxy = vm    // 渲染函数作用域代理
vm._self = vm       // 实例本身

// initLifecycle(vm)    src/core/instance/lifecycle.js **************************************************
vm.$parent = parent
vm.$root = parent ? parent.$root : vm

vm.$children = []
vm.$refs = {}

vm._watcher = null
vm._inactive = null
vm._directInactive = false
vm._isMounted = false
vm._isDestroyed = false
vm._isBeingDestroyed = false

// initEvents(vm)   src/core/instance/events.js **************************************************
vm._events = Object.create(null)
vm._hasHookEvent = false

// initRender(vm)   src/core/instance/render.js **************************************************
vm._vnode = null // the root of the child tree
vm._staticTrees = null // v-once cached trees

vm.$vnode
vm.$slots
vm.$scopedSlots

vm._c
vm.$createElement

vm.$attrs
vm.$listeners

// initState(vm)   src/core/instance/state.js **************************************************
vm._watchers = []
vm._data

代码参考：

https://github.com/vuejs/vue/tree/dev/src/core/instance