Function mountComponent

static/vuejs/vue.runtime.esm.js:2103–2166

(
  vm,
  el,
  hydrating
)

}

function mountComponent (
  vm,
  el,
  hydrating
) {
  vm.$el = el;
  if (!vm.$options.render) {
    vm.$options.render = createEmptyVNode;
    if (process.env.NODE_ENV !== 'production') {
      /* istanbul ignore if */
      if ((vm.$options.template && vm.$options.template.charAt(0) !== '#') ||
        vm.$options.el || el) {
        warn(
          'You are using the runtime-only build of Vue where the template ' +
          'compiler is not available. Either pre-compile the templates into ' +
          'render functions, or use the compiler-included build.',
          vm
        );
      } else {
        warn(
          'Failed to mount component: template or render function not defined.',
          vm
        );
      }
    }
  }
  callHook(vm, 'beforeMount');

  var updateComponent;
  /* istanbul ignore if */
  if (process.env.NODE_ENV !== 'production' && config.performance && mark) {
    updateComponent = function () {
      var name = vm._name;
      var id = vm._uid;
      var startTag = "vue-perf-start:" + id;
      var endTag = "vue-perf-end:" + id;

      mark(startTag);
      var vnode = vm._render();
      mark(endTag);
      measure((name + " render"), startTag, endTag);

      mark(startTag);
      vm._update(vnode, hydrating);
      mark(endTag);
      measure((name + " patch"), startTag, endTag);
    };
  } else {
    updateComponent = function () {
      vm._update(vm._render(), hydrating);
    };
  }

  vm._watcher = new Watcher(vm, updateComponent, noop);
  hydrating = false;

  // manually mounted instance, call mounted on self
  // mounted is called for render-created child components in its inserted hook