87 lines
2.2 KiB
JavaScript
87 lines
2.2 KiB
JavaScript
import { LoggerService } from '../logger/logger'
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export class TimerService {
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constructor() {
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this.loggerService = new LoggerService()
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this.time = 0
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this.rendered = undefined
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}
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initialize(el) {
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if (!el) return
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this.display = el
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this.startTime = undefined
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if (this.id !== undefined) {
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this.stop()
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}
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this.time = 0
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this.render()
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}
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start() {
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if (this.running || !this.display) return
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this.running = true
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this.startTime = Date.now()
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this.tick()
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this.loggerService.debug('started timer')
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}
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stop() {
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this.running = false
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if (this.id !== undefined) {
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window.cancelAnimationFrame(this.id)
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}
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this.id = undefined
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this.loggerService.debug('stopped timer')
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return this.time
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}
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/**
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* Recompute the elapsed time and schedule the next frame.
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* Driven by requestAnimationFrame so it aligns with the browser's paint
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* cadence and pauses automatically when the tab is hidden — instead of the
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* old fixed 1ms interval that fired ~1000 times a second.
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*/
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tick() {
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this.time = Date.now() - this.startTime
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this.render()
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if (this.running) {
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this.id = window.requestAnimationFrame(() => this.tick())
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}
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}
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/**
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* Write to the DOM only when the visible value actually changes. The display
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* has 100ms (tenths-of-a-second) resolution, so most frames are a no-op and
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* cost no reflow.
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*/
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render() {
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if (!this.display) return
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const text = this.pretty(this.time) || '0'
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if (text !== this.rendered) {
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this.display.innerHTML = text
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this.rendered = text
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}
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}
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pretty(duration) {
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if (!duration) return undefined
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var milliseconds = parseInt((duration % 1000) / 100),
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seconds = Math.floor((duration / 1000) % 60),
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minutes = Math.floor((duration / (1000 * 60)) % 60),
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hours = Math.floor((duration / (1000 * 60 * 60)) % 24)
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hours = (hours < 10) ? `0${hours}` : hours
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minutes = (minutes < 10) ? `0${minutes}` : minutes
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seconds = (seconds < 10) ? `0${seconds}` : seconds
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return `${this.clean(hours, ':')}${this.clean(minutes, ':')}${this.clean(seconds, '.')}${this.clean(milliseconds, '')}`
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}
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clean(str, separator) {
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return (str === '00') ? '' : `${str}${separator}`
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}
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}
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