Remove item from array on timeout

Question

I am creating a component to display notifications that should dismiss automatically after a few seconds in Vue, my alert components emits an 'expired' event and then I listen for this event in the parent, and remove it from the parent data array with splice, this works sometimes but sometimes the 'alerts' are not removed.

Vue.component('alert', {
  template: '<li><slot></slot></li>',
  mounted() {
    setTimeout(() => this.$emit('expired'), 2000)
  }
});

new Vue({
  el: '#app',
  data: {
    count: 0,
    alerts: []
  },
  methods: {
        createAlert(){
        this.alerts.push(this.count++)
      },
      removeItem(index) {
        this.alerts.splice(index, 1)
      }
  }
});

See this Fiddle and click on the Create Alert button a couple of times, and some of the alerts won't get dismissed. Any ideas on how to solve this?

Answer 1

As mentioned in the comments, don't do this by index. Here is one alternative.

<div id="app">
  <button @click="createAlert">
    Create Alert
  </button>
  <alert v-for="(alert, index) in alerts" :key="alert.id" :alert="alert" @expired="removeItem(alert)">{{ alert.id }}</alert>
</div>

Vue.component('alert', {
  props: ["alert"],
  template: '<li><slot></slot></li>',
  mounted() {
    setTimeout(() => this.$emit('expired', alert), 2000)
  }
});

new Vue({
  el: '#app',
  data: {
    count: 0,
    alerts: []
  },
  methods: {
        createAlert(){
        this.alerts.push({id: this.count++})
      },
      removeItem(alert) {
        this.alerts.splice(this.alerts.indexOf(alert), 1)
      }
  }
});

Your fiddle revised .