# 初始化

根据上篇Vue函数定义，我们开始讲解_init函数具体作用

  Vue.prototype._init = function (options) {
    var vm = this;
    // a uid
    vm._uid = uid$3++;
    var startTag, endTag;
    /* istanbul ignore if */
    if (config.performance && mark) {
      startTag = "vue-perf-start:" + (vm._uid);
      endTag = "vue-perf-end:" + (vm._uid);
      mark(startTag);
    }
    // a flag to avoid this being observed
    vm._isVue = true;
    // merge options
    if (options && options._isComponent) {
      // optimize internal component instantiation
      // since dynamic options merging is pretty slow, and none of the
      // internal component options needs special treatment.
      initInternalComponent(vm, options);
    } else {
      vm.$options = mergeOptions(
        resolveConstructorOptions(vm.constructor),
        options || {},
        vm
      );
    }
    /* istanbul ignore else */
    {
      initProxy(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 (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);
    }
  };

以上是_init函数的所有内容也就是Vue实例化时做的所有的事, 看起来比较多，我们直接调重点来详细讲解~

TIP

initLifecycle - callHook(vm, 'created')我会在组件篇里说明
vm.$mount是挂载Vue实例的入口函数, 具体我也会在组件篇的patch章节详细说明

关注我, 不迷路

← Vue函数定义合并资源 →