react-event-emitter

DOM CustomEvent emitter written in React. It's meant to be used at any level below the target element in the DOM tree.

Why?

Interacting between React and other libraries can sometimes be a bit cumbersome because of the difference in paradigms. Maybe in the future React will allow to work in an easier way with CustomEvents, but for now you'd need to switch from the usual declarative logic in writting components in JSX to an imperative way to hook up the logic in React and your other library's logic.

It was originally made to interact with CustomElements inside of a React app.

Requirements, installation and usage

You need to have a recent version Node.js installed with a working npm command.

Also, this has react and react-dom as peer dependencies.

To install, run in a shell:

npm install react-event-emitter

Then, in the JavaScript you want to use it, import it as a ES module:

import EventEmitter from 'react-event-emitter';

Or, if you still use commonjs modules for browser code, import it as such:

const EventEmitter = require('react-event-emitter');

To see more, refer to the examples section.

API

props

| name | type | required | default | | ---------- | --------- | -------- | ----------- | | children | ReactNode | no | null | | eventType | string | yes | undefined | | detail | any | no | undefined | | waitUntil | Promise | no | undefined | | bubbles | boolean | no | undefined | | cancelable | boolean | no | undefined | | composed | boolean | no | undefined |

notes

1. To avoid race-conditions, when an event is sent before the element that is supposed to listen to it does so, a waitUntil prop has been introduced.

2. bubbles, cancelable, and composed are directly sent as-is to the CustomEvent constructor, see here for more information.

Example usage

simple

Some DOM element higher up the tree is listening to a load event containing some data

import EventEmitter from 'react-event-emitter';

const Component = ({ data }) => <EventEmitter eventType="load" detail={data} />;

with Custom Elements

In the case where the definition for data-visualisation might not be ready yet (code-splitting and async loading of the definition), but it's the element that is supposed to listen for the emitted event, use the waitUntil prop to wait for its definition to be loaded.

import EventEmitter from 'react-event-emitter';

const Component = ({ data }) => (
  <data-visualisation>
    <EventEmitter
      eventType="load"
      detail={data}
      waitUntil={customElements.whenDefined('data-visualisation')}
    />
  </data-visualisation>
);

Development

Library written in TypeScript.

You can run the tests (unit, linting, and type-checking) by running npm run test.

To build a new bundle, run npm run build, or npm run build:dev for development mode.

Acknowledgement

This package's code was started while working within the Molecular Modeling and Bioinformatics (MMB) group at the Institute for Research in Biomedicine (IRB).