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Vue 'emits' Option


Example

Using the emits option to declare which custom events that are emitted from the component.

export default {
  emits: ['custom-event'],
  methods: {
    notifyParent() {
      this.$emit('custom-event','Hello! ')
    }
  }
}
Run Example »

See more examples below


Definition and Usage

The emits option is used to document what custom events a component emits.

The emits option is not required, which means that a component can emit events without defining them inside the emits option.

Even though the emits option is not required, it is still recommended to have, so that other programmers can easily see what the component emits.

When the emits option is given as an array, the array just consists of the names of the emits as strings. (See the example above.)

When the emits option is given as an object, a property name is the name of an emit, and the value is a validator function if it has one, or 'null' if the emit does not have a validator function. (See the example below.)


More Examples

Example

Using props as objects with options, so that the default food description is shown when it is not provided by the parent component.

FoodItem.vue:

<template>
	<div>
		<h2>{{ foodName }}</h2>
		<p>{{ foodDesc }}</p>
	</div>
</template>

<script>
export default {
	props: {
		foodName: {
			type: String,
			required: true
		},
		foodDesc: {
			type: String,
			required: false,
			default: 'This is the food description...'
		}
	}
};
</script>

App.vue:

<template>
  <h1>Food</h1>
  <p>Food description is not provided for 'Pizza' and 'Rice', so the default description is used.</p>
  <div id="wrapper">
    <food-item 
      food-name="Apples" 
      food-desc="Apples are a type of fruit that grow on trees."/>
    <food-item 
      food-name="Pizza"/>
    <food-item 
      food-name="Rice"/>
  </div> 
</template>

<style>
  #wrapper {
    display: flex;
    flex-wrap: wrap;
  }
  #wrapper > div {
    border: dashed black 1px;
    flex-basis: 120px;
    margin: 10px;
    padding: 10px;
    background-color: lightgreen;
  }
</style>
Run Example »

Related Pages

Vue Tutorial: Vue $emit() Method

Vue Tutorial: Vue Props

Vue Reference: Vue $props Object

Vue Reference: Vue $emit() Method


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