在自定义指令中模拟 v-if 指令 [英] Simulate v-if directive in custom directive

问题描述

我需要销毁像 v-if 这样的自定义指令中的元素.(如果条件失败，则禁止创建项目.)

我正在尝试这个

export const moduleDirective: DirectiveOptions |DirectiveFunction = (el, binding, vnode) =>{const moduleStatus = store.getters[`permissions/${binding.value}Enabled`];如果(！模块状态){const comment = document.createComment(' ');Object.defineProperty(comment, 'setAttribute', {值:() =>不明确的，});vnode.elm = 评论；vnode.text = ' ';vnode.isComment = true;vnode.context = 未定义；vnode.tag = 未定义；如果(el.parentNode){el.parentNode.replaceChild(comment, el);}}};

但是这个选项不适合我.它不会中断组件的创建.

此代码从 DOM 中删除一个元素，但不会销毁组件实例.

解决方案

我没有检查这个但是 来自文档 它应该是这样的.
可能我稍后会用更具体和正确的答案对其进行编辑

Vue.directive('条件', {插入(el，绑定，vnode，oldVnode){/* 当绑定元素插入其父节点时调用(这仅保证父节点存在，不一定在文档中).*/if (!test){ el.remove() }}更新(el，绑定，vnode，oldVnode){/* 在包含组件的 VNode 更新之后调用，但可能在此之前它的孩子已经更新.*/如果 (!test()){ el.remove() }//或者你可以试试这个，改变vnodevnode.props.vIf = test();}}

或者简而言之

Vue.directive('condition', function (el, binding) {if (!test){ el.remove() }})

<块引用>

除了 el 之外，您应该将这些参数视为只读的并且永远不要修改它们.如果需要跨钩子共享信息，建议通过元素的数据集来实现.

I need to destroy element in custom directive like v-if. (Forbid item creation if the condition fails.)

I trying this

export const moduleDirective: DirectiveOptions | DirectiveFunction = (el, binding, vnode) => {
  const moduleStatus = store.getters[`permissions/${binding.value}Enabled`];
  if (!moduleStatus) {
    const comment = document.createComment(' ');
    Object.defineProperty(comment, 'setAttribute', {
      value: () => undefined,
    });
    vnode.elm = comment;
    vnode.text = ' ';
    vnode.isComment = true;
    vnode.context = undefined;
    vnode.tag = undefined;

    if (el.parentNode) {
      el.parentNode.replaceChild(comment, el);
    }
  }
};

But this option does not suit me. It does not interrupt the creation of the component.

this code removes an element from DOM, but not destroy a component instance.

解决方案

I'm not checked this but from doc it should look like this.
probably I will edit it later with a more specific and correct answer

Vue.directive('condition', {


  inserted(el, binding, vnode, oldVnode){
    /* called when the bound element has been inserted into its parent node
      (this only guarantees parent node presence, not necessarily in-document). */

     if (!test){ el.remove() }
  }


  update(el, binding, vnode, oldVnode ){
    /* called after the containing component’s VNode has updated, but possibly before 
       its children have updated. */

     if (!test()){ el.remove() }
    //or you can try this, changed the vnode
    vnode.props.vIf = test();
  }
}

Or in short

Vue.directive('condition', function (el, binding) {
  if (!test){ el.remove() }
})

Apart from el, you should treat these arguments as read-only and never modify them. If you need to share information across hooks, it is recommended to do so through element’s dataset.

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