import EventEmitter from "events" ; export interface ProgressBarState { current : number ; total : number ; startTime : number ; title : string ; rate ( ) : number ; elapsedTime ( since ) : number ; progress ( ) : number ; eta ( ) : number ; isComplete ( ) : boolean ; } export enum Events { TICK = 'tick' , COMPLETED = 'completed' , REACTIVATED = 'reactivated' } export class ProgressBar extends EventEmitter implements ProgressBarState { private _current : number = 0 ; public get current ( ) { return this . _current ; } public set current ( value ) { this . _current = Math . max ( value , 0 ) ; this . checkCompleteEvent ( ) ; } private _total : number = 0 ; public get total ( ) { return this . _total ; } public set total ( value ) { this . _total = Math . max ( value , 0 ) ; this . checkCompleteEvent ( ) ; } private _completeEventEmitted = false ; private get completeEventEmitted ( ) { return this . _completeEventEmitted ; } private set completeEventEmitted ( value ) { if ( this . completeEventEmitted && ! value ) this . emit ( Events . REACTIVATED ) ; this . _completeEventEmitted = value ; } public title : string ; public readonly startTime = Date . now ( ) ; eventNames ( ) { return Object . values ( Events ) ; } constructor ( { current , total , title } = { } ) { super ( ) ; this . current = current ?? this . current ; this . total = total ?? this . total ; this . title = title ?? '' ; this . checkCompleteEvent ( ) ; } private checkCompleteEvent ( ) { if ( this . completeEventEmitted && ! this . isComplete ( ) ) { this . completeEventEmitted = false ; } if ( this . isComplete ( ) && this . current > 0 && ! this . completeEventEmitted ) { this . completeEventEmitted = true ; this . emit ( Events . COMPLETED ) ; } } public tick ( value ) { const incValue = ( this . current + value ) > this . total ? Math . min ( this . total - this . current , value ) : value ; this . current += incValue ; this . emit ( Events . TICK , incValue ) ; } public rate ( ) { const elapsedTime = this . elapsedTime ( Date . now ( ) ) ; return elapsedTime === 0 ? Infinity : this . current / elapsedTime ; } public elapsedTime ( since ) { return since - this . startTime ; } public progress ( ) { return this . current === 0 && this . total === 0 ? 1 : this . current / ( this . total || 1 ) ; } public eta ( ) { return this . isComplete ( ) ? 0 : ( this . elapsedTime ( Date . now ( ) ) * ( this . total / this . current ) ) - this . elapsedTime ( Date . now ( ) ) ; } public isComplete ( ) { return this . current >= this . total ; } }