javascript - 无法访问vue js中的props数据？

Question

您好，我无法访问 Prop 数据。如果我在 chrome vue 开发工具 中看到 props 存在，但无法在创建或安装的钩子(Hook)中访问。

传递 Prop

 <Contradiction 
   :patient="patient" 
   @openForm="toggleFormTable">
 </Contradiction>

矛盾成分

name: "Contradiction",
  props: {
    patient: {
      type: Object,
    },
  },
  data() {
    return {
      patient_id: this.patient.id,
    };
  },
  created() {
    console.log("created hook", this.patient); // shows null
  },
  mounted() {
    console.log("mounted hook", this.patient);//shows null 
  },

我不知道是什么原因，当我在 chrome 开发工具中看到 Patient props 存在但不在 console.log 中时。

Answer 1

从注释中澄清 patent 不是直接在父组件中设置后，您可以将 patent_id 定义为 compulated 属性:

const Contradiction = Vue.component('contradiction', {
  template: '#contradiction',
  props: { patient: { type: Object } },
  computed: {
    patient_id() { if(this.patient) return this.patient.id; }
  }
});

new Vue({
  el: '#app',
  components: { Contradiction },
  data() { return { patient: null } },
  mounted() { setTimeout(() => this.patient = {id:1}, 3000); },
  methods: {
    toggleFormTable() {}
  },
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>

<div id="app">
  <div>
     <Contradiction :patient="patient" @openForm="toggleFormTable"/>
  </div>
</div>

<template id="contradiction">
  <div>patient id: {{patient_id}}</div>
</template>

更好的解决方案是保留您的实现，并且仅在设置了 prop 时才渲染子组件:

const Contradiction = Vue.component('contradiction', {
  template: '#contradiction',
  props: { patient: { type: Object } },
  data() { return { patient_id: this.patient.id } }
});

new Vue({
  el: '#app',
  components: { Contradiction },
  data() { return { patient: null } },
  mounted() { setTimeout(() => this.patient = {id:1}, 3000); },
  methods: {
    toggleFormTable() {}
  },
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>

<div id="app">
  <div>
     <Contradiction v-if="patient" :patient="patient" @openForm="toggleFormTable"/>
  </div>
</div>

<template id="contradiction">
  <div>patient id: {{patient_id}}</div>
</template>