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