Vue.set for array reactively

by robert chang

HTML

<script src="https://cdn.jsdelivr.net/lodash/4.3.0/lodash.min.js"></script>
<script src="https://npmcdn.com/vue@next/dist/vue.js"></script>
<div id="el">
    <item v-for="(ele,index) in items"
      class="ele.id"
      :msg="ele.v"
      :parray = "items"
      :indexinparray="index"
      :key="ele"
      @rm="remove(ele)">
      <span>here is a span{{ ele.id }} with v={{ ele.v }} </span>
    </item>
    
  <pre>
    {{ items }}
  </pre>
</div>

CSS

.container {
  position: relative;
  padding: 0;
}
em{
  background: green;
  color: white;
  cursor: pointer;
}
.item {
  width: 40%;
  height: 30px;
  background-color: #f3f3f3;
  border: 1px solid #666;
  box-sizing: border-box;
}
.fade-move, .fade-enter-active, .fade-leave-active {
  transition: all .5s;
}
.fade-enter {
  opacity: 0;
  transform: scaleY(0) translate(30px, 0);
}
.fade-leave-active {
  position: absolute;
  opacity: 0;
  transform: scaleY(0.01) translate(30px, 0);
}

JavaScript

var items = [{id:1,v:1}, {id:2,v:3}, {id:3,v:5}, {id:4,v:7}, {id:5,v:9}]
var id = items.length + 1

var vm = new Vue({
  el: '#el',
  data: {
    items: items
  },
  components: {
    item: {
      props: ['msg','parray','indexinparray'],
      template: `<div>{{ msg }} <button @click="$emit('rm')">x</button><slot></slot><em @click="moveUp">moveup</em></div>`,
      methods: {
          moveUp: function(){
            var temp = this.parray[this.indexinparray];
            Vue.set(this.parray,this.indexinparray, this.parray[this.indexinparray-1]);
            Vue.set(this.parray,this.indexinparray-1,temp);
            console.log(this.parray);
         }
      }
    }
  },
  methods: {
    remove (item) {
      var i = this.items.indexOf(item)
      if (i > -1) {
        this.items.splice(i, 1)
      }
    }
  }
})