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Andrew
Andrew

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vue-typed-emit

Introduction

A half a year has already passed since I wrote the Vue.js Typed events article. During all this time I was searching for a solution, which doesn't require from a developer to change the way how one is used to emit events in Vue.js components (this.$emit('event', payload)). Finally I've found one, and that's resulted in vue-typed-emit library creation.

Features

The main feature of the library is that it doesn't require from a developer any typed wrappers over a this.$emit invocation. It only requires a simple type which describes names of events your component is supposed to emit along with corresponding payloads.

Here is a trivial example:

import Vue from 'vue'
import { WithEvents } from 'vue-typed-emit'

interface Events {
  foo: string
  bar: [string, number]
  baz: undefined
}

export default (Vue as WithEvents<Events>).extend({
  name: 'Component',
  methods: {
    method() {
      this.$emit('foo', 'foo')
      this.$emit('bar', 0)
      this.$emit('baz')
    },
  },
})

vue-typed-emit verifies that component emits only declared events with valid payloads.

If a developer tries to emit invalid event or invalid payload, one gets an error from TypeScript.

TypeScript error

TypeScript error

You can find vue-type-refs on GitHub and NPM. Feel free to contribute.

Discussion (1)

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romalyt profile image
Roman • Edited on

Hey! Thanks for the article, nice solution.

What do you think about new emits property? It allows you to type hint emits when using with TS. For example:

export default defineComponent({
  emits: {
    'foo': (arg: string) => { // some validation logic for runtime },
  },
  mounted () {
    tis.$emit('foo', 1) // type error, you can emit only strings for 'foo' event
  },
})
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Further reading:
v3.vuejs.org/api/options-data.html...
github.com/vuejs/rfcs/blob/master/...