55 lines
1.6 KiB
TypeScript
55 lines
1.6 KiB
TypeScript
/**
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* @fileoverview A set of helper functions to make it easier to work
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* with events in async/await manner.
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*/
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/**
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* @param {!EventTarget} target
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* @param {string} eventName
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* @return {!Promise<!Event>}
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*/
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export const waitForEvent = (target: EventTarget, eventName: string) => {
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return new Promise(resolve => {
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target.addEventListener(eventName, resolve, { once: true });
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});
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};
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/**
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* @param {!EventEmitter} emitter
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* @param {string} eventName
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* @return {!Promise<!Array>} With Event as the first item.
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*/
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export const emittedOnce = (emitter: NodeJS.EventEmitter, eventName: string, trigger?: () => void) => {
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return emittedNTimes(emitter, eventName, 1, trigger).then(([result]) => result);
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};
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export const emittedNTimes = async (emitter: NodeJS.EventEmitter, eventName: string, times: number, trigger?: () => void) => {
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const events: any[][] = [];
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const p = new Promise<any[][]>(resolve => {
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const handler = (...args: any[]) => {
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events.push(args);
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if (events.length === times) {
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emitter.removeListener(eventName, handler);
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resolve(events);
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}
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};
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emitter.on(eventName, handler);
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});
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if (trigger) {
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await Promise.resolve(trigger());
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}
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return p;
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};
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export const emittedUntil = async (emitter: NodeJS.EventEmitter, eventName: string, untilFn: Function) => {
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const p = new Promise<any[][]>(resolve => {
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const handler = (...args: any[]) => {
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if (untilFn(...args)) {
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emitter.removeListener(eventName, handler);
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resolve(args);
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}
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};
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emitter.on(eventName, handler);
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});
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return p;
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};
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