生命周期 ​

export function initMixin(Vue: typeof Component) {
  Vue.prototype._init = function (options?: Record<string, any>) {
    const vm: Component = this
    // a uid
    vm._uid = uid++

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

    // a flag to mark this as a Vue instance without having to do instanceof
    // check
    vm._isVue = true
    // avoid instances from being observed
    vm.__v_skip = true
    // effect scope
    vm._scope = new EffectScope(true /* detached */)
    vm._scope._vm = 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 as any)
    } else {
      vm.$options = mergeOptions(
        resolveConstructorOptions(vm.constructor as any),
        options || {},
        vm
      )
    }
    /* istanbul ignore else */
    if (__DEV__) {
      initProxy(vm)
    } else {
      vm._renderProxy = vm
    }
    // expose real self
    vm._self = vm
    initLifecycle(vm)
    initEvents(vm)
    initRender(vm)
    callHook(vm, 'beforeCreate', undefined, false /* setContext */)
    initInjections(vm) // resolve injections before data/props
    initState(vm)
    initProvide(vm) // resolve provide after data/props
    callHook(vm, 'created')

    /* istanbul ignore if */
    if (__DEV__ && 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)
    }
  }
}

export function initMixin(Vue: typeof Component) {
  Vue.prototype._init = function (options?: Record<string, any>) {
    const vm: Component = this
    // a uid
    vm._uid = uid++

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

    // a flag to mark this as a Vue instance without having to do instanceof
    // check
    vm._isVue = true
    // avoid instances from being observed
    vm.__v_skip = true
    // effect scope
    vm._scope = new EffectScope(true /* detached */)
    vm._scope._vm = 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 as any)
    } else {
      vm.$options = mergeOptions(
        resolveConstructorOptions(vm.constructor as any),
        options || {},
        vm
      )
    }
    /* istanbul ignore else */
    if (__DEV__) {
      initProxy(vm)
    } else {
      vm._renderProxy = vm
    }
    // expose real self
    vm._self = vm
    initLifecycle(vm)
    initEvents(vm)
    initRender(vm)
    callHook(vm, 'beforeCreate', undefined, false /* setContext */)
    initInjections(vm) // resolve injections before data/props
    initState(vm)
    initProvide(vm) // resolve provide after data/props
    callHook(vm, 'created')

    /* istanbul ignore if */
    if (__DEV__ && 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)
    }
  }
}