V-model doesn't update on checkbox list change-CodePudding

I have a list of checkboxes that are rendered with a v-for on a component. When checked, the checkboxes fill up an array with currently selected checkboxes. The problem comes when one or more of the checked checkboxes is removed - the v-model still counts the removed checkbox. How do I update the v-model as my array updates? I tried force re-rendering the whole component which solves the problem but it's not the solution I need.

  <div v-for="player in players" :key="player.id">
  <input
    v-model="selectedPlayers"
    :value="player.id"
    type="checkbox"
    :id="player.id"
  />
  <label :for="player.id">
    {{ player.name }}
  </label>
</div>

Desired outcome

CodePudding user response：

V-model won't remove data when the component is no longer rendered, you need to do that explicitly.

You could filter selectedPlayers from the @click handler so that it only includes ids that are in the new variable.

this.selectedPlayers = this.selectedPlayers.filter(
  id => players2.find(
    player => player.id === id
  )
)

CodePudding user response：

So from what I understand, you have this player2 array, that you need to compare against. Whatever is there in the players2 array needs to be there in the selectedPlayers array. To do this just use the use map array function to iterate over the players2 array to return only the ids of the players and then store them in the selected players array which being a reactive property will automatically patch the DOM. There's absolutely no need to re-render the component.

Vue.config.productionTip = false;
Vue.config.devtools = false;

new Vue({
  el: "#app",
  data() {
    return {
      selectedPlayers: [],
      players: [
        {name: "Arnold",id: "1"},
        {name: "Rambo",id: 2},
        {name: "Terminator",id: 3},
        {name: "Titan",id: 4},
        {name: "Odin",id: 5},
      ],
      players2: [
        {name: "Titan",id: 4},
        {name: "Odin",id: 5},
      ],
    };
  },
  methods: {
    clicked() {
      this.players = this.players2;
      this.selectedPlayers = this.players2.map(p => p.id);
    }
  }
})

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
<div id="app">
  If you check all checkboxes and press the button, the array still contains all elements
  <div v-for="player in players" :key="player.id">
    <input v-model="selectedPlayers" :key="players.length" :value="player.id" type="checkbox" :id="player.id" />
    <label :for="player.id">
        {{ player.name }}
      </label>
  </div>
  {{ selectedPlayers }}
  <button @click="clicked">Press me</button>
</div>