Working with emits in Vue 3 + Typescript

In this post I will show you'll how to work with emits Vue 3 + Composition API using <script setup>, there's few ways to work with it, let's take a look!

Using the defineEmits() macro we can declare emits like:

1 - Array of strings

<script setup>
const emit = defineEmits(['inFocus', 'submit'])

function buttonClick() {
  emit('submit')
}
</script>

2 - Object syntax

<script setup>
const emit = defineEmits({
  submit(payload) {
    // return `true` or `false` to indicate
    // validation pass / fail
  }
})
</script>

3 - Runtime or base type declaration

<script setup lang="ts">
// runtime
const emit = defineEmits(['change', 'update'])

// type-based (TS)
const emit = defineEmits<{
  (e: 'change', id: number): void
  (e: 'update', value: string): void
}>()
</script>

That's it!

If you want to read and learn more details about component emits declaration, please make sure to visit the Vue 3 official documentation about emits.

See'ya!

---

Article references:
https://vuejs.org/guide/components/events.html
https://vuejs.org/guide/typescript/composition-api.html#typing-component-emits

Comments

[Miko]

Hey there,

Since version 3.3+ type definition for emits is even more clean:

const emit = defineEmits<{
  'change': [id: number]
  'update': [value: string]
}>()
</script>