@wordpress/data
Version:
Data module for WordPress.
47 lines (41 loc) • 870 B
JavaScript
/**
* Create an event emitter.
*
* @return {import("../types").DataEmitter} Emitter.
*/
export function createEmitter() {
let isPaused = false;
let isPending = false;
const listeners = new Set();
const notifyListeners = () =>
// We use Array.from to clone the listeners Set
// This ensures that we don't run a listener
// that was added as a response to another listener.
Array.from( listeners ).forEach( ( listener ) => listener() );
return {
get isPaused() {
return isPaused;
},
subscribe( listener ) {
listeners.add( listener );
return () => listeners.delete( listener );
},
pause() {
isPaused = true;
},
resume() {
isPaused = false;
if ( isPending ) {
isPending = false;
notifyListeners();
}
},
emit() {
if ( isPaused ) {
isPending = true;
return;
}
notifyListeners();
},
};
}