Does the property added by vue through computed do not work by means of modification?

<div id="app">
    <h2>Todos:</h2>
    <ol>
      <li v-for="todo in todosArr">
        <label>
          <input type="checkbox" v-on:change="toggle(todo)" v-bind:checked="todo.show">
          <del v-if="todo.show">
            {{ todo.text }}
          </del>
          <span v-else>
            {{ todo.text }}
          </span>
        </label>
      </li>
    </ol>
  </div>
new Vue({
  el: "-sharpapp",
  data: {
    todos: [
      { text: "Learn JavaScript", done: false},
      { text: "Learn Vue", done: false},
      { text: "Play around in JSFiddle", done: true},
      { text: "Build something awesome", done: true}
    ]
  },
  computed: {
    todosArr: function () {
       var arr = [];
       this.todos.forEach(function(item, index) {
          if(index == 0) {
            item.show = true
            arr.push(item)
          }else{
            item.show = false
            arr.push(item)
          }
       })
       return arr
    }
  },
  methods: {
      toggle: function(todo){
        todo.show = !todo.show
    }
  }
})

demo is here: http://jsfiddle.net/9jxyequ4/
adds the attribute show through computed, modifies show through toggle, but the v-if on the page cannot judge?

May.05,2022

Vue cannot detect new properties of the object, so you need to define the number

at the time of definition.
    todos: [
      { text: "Learn JavaScript", done: false,show:fasle},
      { text: "Learn Vue", done: false,show:false},
      { text: "Play around in JSFiddle", done: true,show:false},
      { text: "Build something awesome", done: true,show:false}
    ]

or use Vue.set

item.show=true
Change

to

Vue.set(item,"show",true)

same as false

MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b4a347-40f7d.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b4a347-40f7d.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?