https://github.com/foxifyjs/events
A high-performance EventEmitter alternative for Node.js and browser
https://github.com/foxifyjs/events
benchmarks browser emitter event eventemitter eventemitter2 eventemitter3 events javascript node nodejs strict-events typescript
Last synced: 17 days ago
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A high-performance EventEmitter alternative for Node.js and browser
- Host: GitHub
- URL: https://github.com/foxifyjs/events
- Owner: foxifyjs
- License: mit
- Created: 2019-03-23T20:23:39.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2023-05-07T09:04:27.000Z (about 2 years ago)
- Last Synced: 2025-04-11T14:01:52.325Z (3 months ago)
- Topics: benchmarks, browser, emitter, event, eventemitter, eventemitter2, eventemitter3, events, javascript, node, nodejs, strict-events, typescript
- Language: JavaScript
- Homepage: https://foxifyjs.github.io/events
- Size: 1.57 MB
- Stars: 19
- Watchers: 2
- Forks: 2
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Events
`@foxify/events` is a `EventEmitter` alternative for `Node.js` and `browser` that has been optimized for better
performance compared to the native version.
[![Build Status][BUILD_BADGE]][BUILD_URI]
[![Coverage Status][COVERAGE_BADGE]][COVERAGE_URI]
[![NPM Version][VERSION_BADGE]][NPM_URI]
[![npm bundle size (minified)][MINIFIED_BADGE]][NPM_URI]
[![npm bundle size (minified + gzip)][GZIP_BADGE]][NPM_URI]
[![NPM Monthly Downloads][MONTHLY_DOWNLOADS_BADGE]][NPM_URI]
[![NPM Total Downloads][TOTAL_DOWNLOADS_BADGE]][NPM_URI]
[![Dependencies Status][DEPENDENCY_STATUS_BADGE]][DEPENDENCY_STATUS_URI]
[![Open Issues][OPEN_ISSUES_BADGE]][OPEN_ISSUES_URI]
[![Pull Requests][PR_BADGE]][PR_URI]
[![License][LICENSE_BADGE]][LICENSE_URI]
This module is API compatible with the `EventEmitter` that ships by default with Node.js but there are some slight
differences:
- The `newListener` and `removeListener` events have been removed as they are useful only in some uncommon use-cases.
- The `setMaxListeners` and `getMaxListeners` methods are not available.
- Support for custom context for events so there is no need to use `bind`.
- Support for strict events in `TypeScript`.
## Table of Contents
- [Installation](#installation)
- [Usage](#usage)
- [Strict events](#strict-events)
- [Contextual emits](#contextual-emits)
- [Benchmarks](#benchmarks)
- [Tests](#tests)
- [Coverage](#coverage)
- [Versioning](#versioning)
- [Authors](#authors)
- [License](#license)
## Installation
```shell
npm i @foxify/events
```
## Usage
JavaScript:
```javascript
const EventEmitter = require("@foxify/events").default;
```
TypeScript:
```typescript
import EventEmitter from "@foxify/events";
```
For the API documentation, please follow the official Node.js [documentation](https://nodejs.org/api/events.html).
### Strict events
> "error" event is always defined by default because of its different behavior
first create events type (optional)
```typescript
type Events = {
foo: (bar: string) => void;
withContextEnforcement: (this: number, bar: number) => void;
}
```
then create a new direct/extended instance
```typescript
const eventEmitter = new EventEmitter();
```
```typescript
class Emitter extends EventEmitter {
}
const eventEmitter = new Emitter();
```
then start emitting & listening to events
```typescript
// Works just fine. so don't worry about "ImplicitAny" config, since type of "bar" is defined as "string"
eventEmitter.on("foo", bar => 1);
// This works fine as well
eventEmitter.on("withContextEnforcement", function (bar) {
return this + bar;
}, 1);
// Throws an error (TS compile time), since this event requires the "bar" argument of type "string"
eventEmitter.emit("foo");
// Works just fine
eventEmitter.emit("foo", "bar");
```
### Contextual emits
We've upgraded the API of the `on`, `once`, `addListener`, `prependListener` and
`prependOnceListener` to accept an extra argument which is the `context`
or `this` value that should be set for the emitted events. This means you no longer have the overhead of an event that
required `bind` in order to get a custom `this` value.
```javascript
const eventEmitter = new EventEmitter();
const context = { foo: "bar" };
function listener() {
console.log(this === context); // true
}
eventEmitter.on("event:1", listener, context);
eventEmitter.once("event:2", listener, context);
eventEmitter.addListener("event:3", listener, context);
eventEmitter.prependListener("event:4", listener, context);
eventEmitter.prependOnceListener("event:5", listener, context);
```
## Benchmarks
```shell
npm run benchmarks
```
## Tests
```shell
npm test
```
## Coverage
```shell
npm run test:coverage
```
## Versioning
We use [SemVer](http://semver.org) for versioning. For the versions available, see
the [releases on this repository](https://github.com/foxifyjs/events/releases).
## Authors
- **Ardalan Amini** - *Core Maintainer* - [@ardalanamini](https://github.com/ardalanamini)
See also the list of [contributors](https://github.com/foxifyjs/events/contributors) who participated in this project.
## License
This project is licensed under the MIT License - see the [LICENSE][LICENSE_URI] file for details
[BUILD_BADGE]: https://github.com/foxifyjs/events/workflows/Test/badge.svg
[BUILD_URI]: https://github.com/foxifyjs/events/actions
[COVERAGE_BADGE]: https://codecov.io/gh/foxifyjs/events/branch/master/graph/badge.svg
[COVERAGE_URI]: https://codecov.io/gh/foxifyjs/events
[VERSION_BADGE]: https://img.shields.io/npm/v/@foxify/events.svg
[MINIFIED_BADGE]: https://img.shields.io/bundlephobia/min/@foxify/events.svg
[GZIP_BADGE]: https://img.shields.io/bundlephobia/minzip/@foxify/events.svg
[MONTHLY_DOWNLOADS_BADGE]: https://img.shields.io/npm/dm/@foxify/events.svg
[TOTAL_DOWNLOADS_BADGE]: https://img.shields.io/npm/dt/@foxify/events.svg
[DEPENDENCY_STATUS_BADGE]: https://david-dm.org/foxifyjs/events.svg
[DEPENDENCY_STATUS_URI]: https://david-dm.org/foxifyjs/events
[OPEN_ISSUES_BADGE]: https://img.shields.io/github/issues-raw/foxifyjs/events.svg
[OPEN_ISSUES_URI]: https://github.com/foxifyjs/events/issues?q=is%3Aopen+is%3Aissue
[PR_BADGE]: https://img.shields.io/badge/PRs-Welcome-brightgreen.svg
[PR_URI]: https://github.com/foxifyjs/events/pulls
[LICENSE_BADGE]: https://img.shields.io/github/license/foxifyjs/events.svg
[LICENSE_URI]: https://github.com/foxifyjs/events/blob/master/LICENSE
[NPM_URI]: https://www.npmjs.com/package/@foxify/events