Update count for objects in nested array in vue

Question

I'm using vue-cli and I'm trying to figure out how to update counter in my template:

<div v-for="(item, index) in outerArray" :key="item.id" v-bind:id="item.name">
   <div>  <p> {{ item.name }}</p> </div>
<div>Count:{{count}}</div>

I would like the counter to update for each user based off of how many alerts are in warning array:

outerArray:[
             { name: 'Ray',
               count: null,
               warning: [{time: '2:00', alert: 'G: 150',},
                         {time: '7:00', alert: 'RR: 38',}]
              },
             { name: 'Mike',
               count: null,
               warning:[{time: '9:00',alert: 'G: 40',}]
             },
    
            ]

So the output should look like:

Ray           Mike
Count:2       Count:1

Any help would be appreciated, thanks!

Update

I used:

this.outerArray[index].warning.length

to display how many alerts were in warnings.

muka.gergely · Accepted Answer · 2020-07-14 20:27:02Z

2

If this value only changes from item to item, then:

new Vue({
  el: "#app",
  data: {
    outerArray: [{
        name: 'Ray',
        count: null,
        warning: [{
            time: '2:00',
            alert: 'G: 150',
          },
          {
            time: '7:00',
            alert: 'RR: 38',
          }
        ]
      },
      {
        name: 'Mike',
        count: null,
        warning: [{
          time: '9:00',
          alert: 'G: 40',
        }]
      },
    ]
  },
  methods: {
    countWarnings(item) {
      return item.warning.length
    }
  },
  mounted() {
    this.outerArray.forEach(e => {
      e.count = e.warning.length
    })
  }
})

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
<div id="app">
  <div v-for="(item, index) in outerArray" :key="item.id" v-bind:id="item.name">
    <div>
      <p>{{ item.name }}</p>
    </div>
    <div>Count (from item.warning): {{ item.warning.length }}</div>
    <div>Count (with item.count set at mounted): {{ item.count }}</div>
    <div>Count (with a count method): {{ countWarnings(item) }}</div><br />
    If you're not sure, what a variable holds, you can either use the Vue extension (in Chrome), the console or the screen:<br />
    - The item is: {{ item }}<br />
    - The item.warning is: {{ item.warning }}<br />
    - The item.warning.length is: {{ item.warning.length }}
    <br />
    <hr />
  </div>
</div>

edited Jul 14, 2020 at 20:27

answered Jul 14, 2020 at 20:21

muka.gergely

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1 Comment

muka.gergely Over a year ago

@YJay I’m happy that I could help!

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