42 lines
1 KiB
JavaScript
42 lines
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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