React Global Event Listener

A higher order component for subscribing listeners to events

Install

yarn

yarn add react-global-event-listener

npm

npm install react-global-event-listener

Use Case

You want multiple components listening for events on the same element(s) using something like _.debounce or _.throttle but you don't want to eat the cost of creating N debounced listeners for your N components. react-global-event-listener creates just one listener wrapped with your wrapper per (element, event) combination and dispatches the event to every subscribed component.

Example

import React from 'react'
import _ from 'lodash'
import { withGlobalEventListener } from 'react-global-event-listener'

class Feed extends React.Component {
  componentWillMount() {
    this.props.subscribeListener(
      window, 
      'scroll', 
      'window.scroll',
      'Feed.onScroll', 
      this.onScroll,
      {listenerWrapper: _.partialRight(_.throttle, 200)}
    )
  }
  
  componentWillUnmount() {
    this.props.unsubscribeListener(
      window,
      'window.scroll',
      'Feed.onScroll'
    )
  }
  
  onScroll = () => {
    // load the next items when we reach the bottom of the feed
  }
  
  render() {
    return (
      <div>
        {this.props.items.map(item => item.title)}
      </div>
    )
  }
}

export default withGlobalEventListener(Feed)

API

The component will be passed two function props:

function subscribeListener(element, eventName, listenerKey, funcKey, func, {listenerWrapper}) {}

function unsubscribeListener(element, listenerKey, funcKey) {}

Arguments

element - DOM element - The element to call addEventListener on

eventName - string - The event to listen for

funcKey - string - A key for element.eventName that should be the same for all subscribers to the (element, eventName) tuple. This helps us not store DOM elements in our lookup dictionary.

funcKey - string - A key for the func that should be unique for all subscribers of the (element, eventName) tuple. This is used for unsubscribing functions.

func - function - The function you want to subscribe to the event. Will be called with event.

Options

listenerWrapper - function - Function to wrap the handler used in the call to addEventListener. Should return another function: f => g(event). Useful when you want to throttle or debounce the event listeners. Since this is applied on the handler to addEventListener, this will affect all downstream subscribers.
The first component to call subscribeListener is the one that creates the handler and applies the wrapper.