42 lines
1.1 KiB
JavaScript
42 lines
1.1 KiB
JavaScript
/**
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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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const waitForEvent = (target, eventName) => {
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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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const emittedOnce = (emitter, eventName) => {
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return emittedNTimes(emitter, eventName, 1).then(([result]) => result);
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};
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const emittedNTimes = (emitter, eventName, times) => {
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const events = [];
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return new Promise(resolve => {
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const handler = (...args) => {
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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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};
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exports.emittedOnce = emittedOnce;
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exports.emittedNTimes = emittedNTimes;
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exports.waitForEvent = waitForEvent;
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