Vue高级用法实例教程之动态组件

// vue
<div id="app">
  <button @click="changeTabs('child1')">child1</button>
  <button @click="changeTabs('child2')">child2</button>
  <button @click="changeTabs('child3')">child3</button>
  <component :is="chooseTabs">
  </component>
</div>

// js
var child1 = {
  template: '<div>content1</div>',
}
var child2 = {
  template: '<div>content2</div>'
}
var child3 = {
  template: '<div>content3</div>'
}
var vm = new Vue({
  el: '#app',
  components: {
    child1,
    child2,
    child3
  },
  methods: {
    changeTabs(tab) {
      this.chooseTabs = tab;
    }
  }
})

//  针对动态组件的解析
function processComponent (el) {
  var binding;
  // 拿到is属性所对应的值
  if ((binding = getBindingAttr(el, 'is'))) {
    // ast树上多了component的属性
    el.component = binding;
  }
  if (getAndRemoveAttr(el, 'inline-template') != null) {
    el.inlineTemplate = true;
  }
}

// render函数生成函数
var code = generate(ast, options);

// generate函数的实现
function generate (ast,options) {
  var state = new CodegenState(options);
  var code = ast ? genElement(ast, state) : '_c("div")';
  return {
    render: ("with(this){return " + code + "}"),
    staticRenderFns: state.staticRenderFns
  }
}

function genElement(el, state) {
  ···
  var code;
  // 动态组件分支
  if (el.component) {
    code = genComponent(el.component, el, state);
  }
}

// 针对动态组件的处理
  function genComponent (
    componentName,
    el,
    state
  ) {
    // 拥有inlineTemplate属性时，children为null
    var children = el.inlineTemplate ? null : genChildren(el, state, true);
    
    return ("_c(" + componentName + "," + (genData$2(el, state)) + 
    (children ? ("," + children) : '') + ")")
  }

"with(this){return _c('div',{attrs:{"id":"app"}},[_c('child1',[_v(_s(test))])],1)}"

"with(this){return _c('div',{attrs:{"id":"app"}},[_c(chooseTabs,{tag:"component"})],1)}"

const AsyncComponent = () => ({

  // 需要加载的组件 (应该是一个 `Promise` 对象)

  component: import('./MyComponent.vue'),

  // 异步组件加载时使用的组件

  loading: LoadingComponent,

  // 加载失败时使用的组件

  error: ErrorComponent,

  // 展示加载时组件的延时时间。默认值是 200 (毫秒)

  delay: 200,

  // 如果提供了超时时间且组件加载也超时了，

  // 则使用加载失败时使用的组件。默认值是：`Infinity`

  timeout: 3000

});



components: {

  AsyncComponent,

},