# evt

> Type safe replacement for node's EventEmitter

Latest version **2.5.9** (published 2025-01-15) · MIT license · 0 weekly downloads

## Install

```sh
npm install evt
pnpm add evt
yarn add evt
bun add evt
```

## Health

**Score 35/100 (D)** — status: maintenance-mode.

Positive: has types; esm support; no vulnerabilities.

Warnings: low downloads.

Negative: stale; low maintenance score.

## Facts

| | |
|---|---|
| Version | 2.5.9 |
| Published | 2025-01-15 |
| First published | 2013-02-21 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | bundled |
| Module format | ESM + CommonJS |
| Dependencies | 3 |
| Unpacked size | 1.9 MB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 462 |
| Author | u/garronej |
| Maintainers | xananax, garronej |
| Keywords | deno, EventEmitter, typescript, functional programming, qt signal, events, ts-evt, async-await, promise, rxjs |

## Links

- npm: https://www.npmjs.com/package/evt
- Repository: https://github.com/garronej/evt
- Homepage: https://evt.land
- Issues: https://github.com/garronej/evt/issues
- npm.io page: https://npm.io/package/evt

## Dependencies (3)

- [tsafe](https://npm.io/package/tsafe.md) ^1.8.5
- [run-exclusive](https://npm.io/package/run-exclusive.md) ^2.2.19
- [minimal-polyfills](https://npm.io/package/minimal-polyfills.md) ^2.2.3

## Alternatives

- [async-exit-hook](https://npm.io/package/async-exit-hook.md) — 3.7M weekly downloads
- [evnty](https://npm.io/package/evnty.md) — 7.2K weekly downloads
- [eleventy-plugin-asciidoc](https://npm.io/package/eleventy-plugin-asciidoc.md) — 3.5K weekly downloads
- [@jswork/next-get2get](https://npm.io/package/@jswork/next-get2get.md) — 945 weekly downloads
- [@dashersw/axon](https://npm.io/package/@dashersw/axon.md) — 934 weekly downloads

## Recent versions

- 2.5.9 (latest) — 2025-01-15
- 2.4.21-rc.0 (next) — 2023-05-22
- 2.0.0-beta.45 (beta) — 2022-07-03
- 2.5.8 — 2024-11-18
- 2.5.7 — 2024-01-15
- 2.5.6 — 2024-01-09
- 2.5.5 — 2024-01-08
- 2.5.3 — 2023-09-29
- 2.5.2 — 2023-09-10
- 2.5.1 — 2023-09-10
- 2.5.0 — 2023-09-07
- 2.4.23 — 2023-09-06
- 2.4.22 — 2023-05-25
- 2.4.21 — 2023-05-22
- 2.4.20 — 2023-05-21
- … 171 more at https://npm.io/package/evt/versions

## README

<p align="center">
    <img src="https://user-images.githubusercontent.com/6702424/76674598-91ebfc00-65b1-11ea-88df-eb43f04f3cce.png">
</p>
<p align="center">
    💧<i>EventEmitter's typesafe replacement</i>💧
    <br>
    <br>
    <a href="https://github.com/garronej/evt/actions">
      <img src="https://github.com/garronej/evt/workflows/ci/badge.svg?branch=main">
    </a>
    <a href="https://deno.land/x/evt">
        <img src="https://img.shields.io/endpoint?url=https%3A%2F%2Fdeno-visualizer.danopia.net%2Fshields%2Flatest-version%2Fx%2Fevt%2Fmod.ts">
    </a>
    <a href="https://www.npmjs.com/package/evt">
      <img src="https://img.shields.io/npm/v/evt?logo=npm">
    </a>
    <a href="https://bundlephobia.com/package/evt">
      <img src="https://img.shields.io/bundlephobia/minzip/evt">
    </a>
    <a href="https://www.npmjs.com/package/evt">
      <img src="https://img.shields.io/npm/dm/evt">
    </a>
    <a href="https://github.com/garronej/evt/blob/main/LICENSE">
      <img src="https://img.shields.io/npm/l/evt">
    </a>
</p>

</p>
<p align="center">
  <a href="https://www.evt.land">Home</a>
  -
  <a href="https://docs.evt.land">Documentation</a>
</p>

---

`'evt'` is intended to be a replacement for `'events'`.  
It makes heavy use of **typescript**'s type inference features to provide **type safety** while keeping things **concise and elegant** 🍸.

<b>Suitable for any JS runtime env (deno, node, old browsers, react-native ...)</b>
- ✅ It is both a [Deno](https://deno.land/x/evt) and an [NPM](https://www.npmjs.com/evt) module. ( Achieved with [Denoify](https://github.com/garronej/denoify) ) 
- ✅ No external dependencies ([`tsafe`](https://github.com/garronej/tsafe), [`run-exclusive`](https://github.com/garronej/run_exclusive) and [`minimal-polyfills`](https://github.com/garronej/minimal_polyfills) are all from the same author as EVT).
- ✅ [Makes it easy to work with events in React](https://docs.evt.land/react-hooks).  

Can be imported in TypeScript projects using version TypeScript >= 3.8 (February 20th, 2020) and in any plain JS projects.

> NOTE: There is very few breaking changes from v1 to v2. [Check them out](https://docs.evt.land/v1-greater-than-v2).  

# Who is using it

<p align="center">
    <a href="https://connext.network">
        <img src="https://user-images.githubusercontent.com/6702424/84102640-4e1e5c80-aa11-11ea-9d13-df0a65c8cdaf.png">
    </a>
    <a href="https://www.semasim.com">
        <img src="https://user-images.githubusercontent.com/6702424/84102785-aead9980-aa11-11ea-915b-5c4a5282c44e.png"> 
    </a>
    <br>
    <a href="https://thegraph.com">
        <img src="https://user-images.githubusercontent.com/6702424/179356567-19e2ca0a-9797-4c82-8a45-7e1d0de896a9.png"> 
    </a>
    <a href="https://insee.fr">
        <img src="https://user-images.githubusercontent.com/6702424/117936881-a9358f00-b305-11eb-84b9-e61593632bdd.png"> 
    </a>
    <a href="https://www.etalab.gouv.fr/">
        <img src="https://user-images.githubusercontent.com/6702424/179345089-3aee6170-e7aa-4b38-adf1-f7d132aa7be4.png"> 
    </a>
</p>

# Install / Import

## In Deno:
```typescript
import { Evt } from "https://deno.land/x/evt/mod.ts";
```
## Anywhere else:
```bash
$ npm install --save evt
```
```typescript
import { Evt } from "evt"; 
```

# Try it

<p align="center">
    <img src="https://user-images.githubusercontent.com/6702424/179363007-582acf54-8f83-42ac-a062-562f8de40d14.gif">  
    <a href="https://stackblitz.com/edit/evt-playground-gfnidx?file=index.ts">Playground</a>
</p>

# Motivations

There are a lot of things that can't easily be done with `EventEmitter`:

* Enforcing **type safety**.
* Removing a particular listener ( if the callback is an anonymous function ).
* Adding a one-time listener for the next event that meets a condition.
* Waiting \(via a Promise\) for one thing or another to happen.  
_Example: waiting at most one second for the next message, stop waiting if the socket disconnects._

Why would someone pick EVT over RxJS:  

* EVT's learning curve is not as steep as RxJS's. 
* Generates code that is easier to grasp for people not familiar with reactive programming.

EVT is an attempt to address all these points while trying to remain as accessible as `EventEmitter`.  
  
</br>

<p align="center">
  <a href="https://evt.land">Get Started</a>
</p>

# The sticker

<p align="center">
    <img src="https://user-images.githubusercontent.com/6702424/90626180-e3607d00-e21a-11ea-9c88-82880ac9cedf.png">  
</p>
<p align="center">
    <a href="https://teespring.com/fr/evt-sticker">Shop</a>
</p>

---
_Source: https://npm.io/package/evt · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._