React-sub-unsub NPM

Documentation

Overview

Take all the frustration (and memory leaks) out of adding and removing listeners in React!

With this library, you can easily manage listeners, JS timers (intervals, timeouts), and anything else that follows the subscribe/unsubscribe pattern in your React effects.

Simply use an instance of the Subs class in this library to subscribe to events or timers. All unsubscribe functions are stored for later.

When it's time to unsubscribe all listeners, just call unsubAll() to remove all listeners and clear all timers. Easy as that.

You can also create a cleanup function using createCleanup() that will unsubscribe all listeners when called. This is particularly handy when used as the return value for React effects.

For finer control or one-off subscriptions, you can use the static functions in the Subscribe class.

See below for examples and more.

Features include:

🔔 Quickly and easily subscribe and unsubscribe to and from events
- An easy way to subscribe and unsubscribe to/from events in JavaScript.
💁‍♀️ Covers common use cases, as well as custom ones
- Built-in support for EventEmitter and DOM events, and custom.
⏰ Timeout and interval support
- Includes support for setTimeout and setInterval to make life easier.
⚛️ Perfect for React effects
- Makes adding/removing listeners and timers in React effects a breeze.
👍 Simple, flexible, and convenient
- Use static functions yourself via Subscribe, or a Subs instance for ultimate convenience.

Donate

If this project helped you, please consider buying me a coffee or sponsoring me. Your support is much appreciated!

Installation

npm i react-sub-unsub

Quick Start

Below is a full example of adding/removing listeners in a React effect using the Subs class.

In this example, we will subscribe to an event emitter, a DOM event, and a custom listener interface, as well as some timers.

At the end of the effect, we will return a cleanup function that unsubscribes all listeners and timers using createCleanup().

import React from 'react';
import { EventEmitter } from 'events';

import { Subs } from 'react-sub-unsub';

export const eventEmitter = new EventEmitter();
export const MyComponent = (props: any) => {
  React.useEffect(() => {
    // Listener functions
    const myEventListener = () => {
      console.log('My event fired!');
    };
    const keyPressListener = (e: any) => {
      console.log('Key pressed!', e);
    };
    const bodySizeListener = (e: any) => {
      console.log('Body size changed!', e);
    };

    // Use this object to subscribe and unsubscribe
    const subs = new Subs();

    // ➡️ Event emitter subscription
    subs.subscribeEvent(eventEmitter, 'my-event', myEventListener);

    // ➡️ DOM event subscription
    subs.subscribeDOMEvent(document, 'keypress', keyPressListener);

    // ➡️ Custom listener interface subscription
    subs.subscribe(() => {
      const resizeObserver = new ResizeObserver(bodySizeListener);
      const targetElement = document.getElementsByTagName('body')[0];
      resizeObserver.observe(targetElement);
      return () => resizeObserver.unobserve(targetElement);
    });

    // ➡️ setTimeout subscription
    subs.setTimeout(() => {
      console.log('Timeout fired!');
    }, 2000);

    // ➡️ setInterval subscription
    subs.setInterval(() => {
      console.log('Interval fired!');
    }, 1000);

    // You can access all unsubscribe functions directly via `subs.list`
    console.log(`There are ${subs.list.length} subscriptions!`);

    // Return a cleanup function that unsubscribes all listeners and timers
    return subs.createCleanup();
  }, []);

  // ...

  return <div>My Component!</div>;
};

If you need to perform other cleanup in your effect's return function, you can unsubscribe all listeners manually by calling subs.unsubAll(), like so:

// Effect cleanup function
return () => {
  subs.unsubAll();
  // ... Custom cleanup
};

Static Functions

If you'd like to call the functions used by Subs manually, you can use the static functions available in the Subscribe class:

import { Subscribe } from 'react-sub-unsub';

Call any of the following:

Subscribe.subscribe - Call provided function to subscribe to an event and return an unsubscribe function.
Subscribe.subscribeEvent - Subscribe to an emitter event and return an unsubscribe function.
Subscribe.subscribeDOMEvent - Subscribe to a DOM event and return an unsubscribe function.
Subscribe.setTimeout - Create a subscription using setTimeout, return an unsubscribe function.
Subscribe.setInterval - Create a subscription using setInterval, return an unsubscribe function.
Subscribe.unsubAll - Call all provided unsubscribe functions (array or single unsubscribe).
Subscribe.createCleanup - Create and return a cleanup function that, when called, calls all unsubscribe functions provided.

See the JS docs for each for more details.

TypeScript

Type definitions have been included for TypeScript support.

Icon Attribution

Favicon by Twemoji.

Contributing

Open source software is awesome and so are you. 😎

Feel free to submit a pull request for bugs or additions, and make sure to update tests as appropriate. If you find a mistake in the docs, send a PR! Even the smallest changes help.

For major changes, open an issue first to discuss what you'd like to change.