Vuejs和Vue.set()，更新数组 [英] Vuejs and Vue.set(), update array

问题描述

我是Vuejs的新手.做了些什么，但我不知道这是简单/正确的方法.

I'm new to Vuejs. Made something, but I don't know it's the simple / right way.

我想要的

我想要数组中的一些日期，并在事件中更新它们.首先，我尝试了Vue.set，但没有成功.现在，在更改我的数组项之后:

I want some dates in an array and update them on a event. First I tried Vue.set, but it dind't work out. Now after changing my array item:

this.items[index] = val;
this.items.push();

我没有将push()推送到数组，而是会更新.但是有时最后一项会被隐藏，以某种方式...我认为此解决方案有点过分棘手，如何使其稳定?

I push() nothing to the array and it will update.. But sometimes the last item will be hidden, somehow... I think this solution is a bit hacky, how can I make it stable?

简单的代码在这里:

new Vue({
  el: '#app',
  data: {
  	f: 'DD-MM-YYYY',
    items: [
      "10-03-2017",
      "12-03-2017"
    ]
  },
  methods: {
    
    cha: function(index, item, what, count) {
    	console.log(item + " index > " + index);
      val = moment(this.items[index], this.f).add(count, what).format(this.f);
  		this.items[index] = val;
      this.items.push();
      console.log("arr length:  " + this.items.length);
    }
  }
})

ul {
  list-style-type: none;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/1.0.11/vue.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.10.6/moment.min.js"></script>
<div id="app">
  <ul>
    <li v-for="(index, item) in items">
    <br><br>
      <button v-on:click="cha(index, item, 'day', -1)">
      - day</button>
      {{ item }}
      <button v-on:click="cha(index, item, 'day', 1)">
      + day</button>
    <br><br>
    </li>
  </ul>
</div>

推荐答案

如果您像这样操作数组，VueJS将无法对状态进行更改.

VueJS can't pickup your changes to the state if you manipulate arrays like this.

如常见的初学者中所述，您应该使用类似数组的方法推送，拼接或其他操作，并且永远不要修改像a[2] = 2这样的索引或数组的.length属性.

As explained in Common Beginner Gotchas, you should use array methods like push, splice or whatever and never modify the indexes like this a[2] = 2 nor the .length property of an array.

new Vue({
  el: '#app',
  data: {
    f: 'DD-MM-YYYY',
    items: [
      "10-03-2017",
      "12-03-2017"
    ]
  },
  methods: {

    cha: function(index, item, what, count) {
      console.log(item + " index > " + index);
      val = moment(this.items[index], this.f).add(count, what).format(this.f);

      this.items.$set(index, val)
      console.log("arr length:  " + this.items.length);
    }
  }
})

ul {
  list-style-type: none;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/1.0.11/vue.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.10.6/moment.min.js"></script>
<div id="app">
  <ul>
    <li v-for="(index, item) in items">
      <br><br>
      <button v-on:click="cha(index, item, 'day', -1)">
      - day</button> {{ item }}
      <button v-on:click="cha(index, item, 'day', 1)">
      + day</button>
      <br><br>
    </li>
  </ul>
</div>

这篇关于Vuejs和Vue.set()，更新数组的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！