87 lines
3.0 KiB
JavaScript
87 lines
3.0 KiB
JavaScript
const getObserversByPriority = ( observers, eventType ) => {
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return observers[ eventType ]
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? Array.from( observers[ eventType ].values() ).sort( ( a, b ) => {
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return a.priority - b.priority;
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} )
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: [];
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};
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/**
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* Emits events on registered observers for the provided type and passes along
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* the provided data.
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*
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* This event emitter will silently catch promise errors, but doesn't care
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* otherwise if any errors are caused by observers. So events that do care
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* should use `emitEventWithAbort` instead.
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*
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* @param {Object} observers The registered observers to omit to.
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* @param {string} eventType The event type being emitted.
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* @param {*} data Data passed along to the observer when it is
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* invoked.
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*
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* @return {Promise} A promise that resolves to true after all observers have
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* executed.
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*/
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export const emitEvent = async ( observers, eventType, data ) => {
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const observersByType = getObserversByPriority( observers, eventType );
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const observerResponses = [];
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for ( const observer of observersByType ) {
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try {
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const observerResponse = await Promise.resolve(
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observer.callback( data )
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);
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if ( typeof observerResponse === 'object' ) {
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observerResponses.push( observerResponse );
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}
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} catch ( e ) {
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// we don't care about errors blocking execution, but will
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// console.error for troubleshooting.
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// eslint-disable-next-line no-console
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console.error( e );
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}
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}
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return observerResponses.length ? observerResponses : true;
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};
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/**
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* Emits events on registered observers for the provided type and passes along
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* the provided data. This event emitter will abort and return any value from
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* observers that do not return true.
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*
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* @param {Object} observers The registered observers to omit to.
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* @param {string} eventType The event type being emitted.
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* @param {*} data Data passed along to the observer when it is
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* invoked.
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*
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* @return {Promise} Returns a promise that resolves to either boolean or the
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* return value of the aborted observer.
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*/
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export const emitEventWithAbort = async ( observers, eventType, data ) => {
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const observersByType = getObserversByPriority( observers, eventType );
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let emitterResponse = true;
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for ( const observer of observersByType ) {
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try {
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const response = await Promise.resolve( observer.callback( data ) );
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if (
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typeof response === 'object' &&
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typeof response.type === 'undefined'
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) {
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throw new Error(
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'If you want to abort event emitter processing, your observer must return an object with a type property'
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);
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}
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emitterResponse = typeof response === 'object' ? response : true;
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if ( emitterResponse !== true ) {
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return emitterResponse;
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}
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} catch ( e ) {
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// we don't handle thrown errors but just console.log for
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// troubleshooting
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// eslint-disable-next-line no-console
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console.error( e );
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return { type: 'error' };
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}
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}
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return emitterResponse;
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};
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