forked from cybrespace/pinafore
44 lines
1.2 KiB
JavaScript
44 lines
1.2 KiB
JavaScript
// Wrapper to call requestIdleCallback() to schedule low-priority work.
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// See https://developer.mozilla.org/en-US/docs/Web/API/Background_Tasks_API
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// for a good breakdown of the concepts behind this.
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import Queue from 'tiny-queue'
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import { mark, stop } from './marks'
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const taskQueue = new Queue()
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let runningRequestIdleCallback = false
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const liteRIC = cb => setTimeout(() => cb({timeRemaining: () => Infinity})) // eslint-disable-line
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function getRIC () {
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// we load polyfills asynchronously, so there's a tiny chance this is not defined
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return typeof requestIdleCallback !== 'undefined' ? requestIdleCallback : liteRIC
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}
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function runTasks (deadline) {
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mark('scheduleIdleTask:runTasks()')
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while (taskQueue.length && deadline.timeRemaining() > 0) {
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let task = taskQueue.shift()
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try {
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task()
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} catch (e) {
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console.error(e)
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}
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}
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if (taskQueue.length) {
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let rIC = getRIC()
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rIC(runTasks)
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} else {
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runningRequestIdleCallback = false
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}
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stop('scheduleIdleTask:runTasks()')
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}
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export function scheduleIdleTask (task) {
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taskQueue.push(task)
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if (!runningRequestIdleCallback) {
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runningRequestIdleCallback = true
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let rIC = getRIC()
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rIC(runTasks)
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}
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}
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