时间CountDown在角度2

Question

我希望这样的日期倒计时：

http://codepen.io/garethdweaver/pen/eNpWBb

但是在角度2中，我发现这个plunkr每500毫秒增加一个数字：

https://plnkr.co/edit/pVMEbbGSzMwSBS4XEXJI?p=preview

这是代码：

import {Component,Input} from 'angular2/core';
import {Observable} from 'rxjs/Rx';

@Component({
    selector: 'my-app',
    template: `
      <div>
        {{message}}
      </div>
    `
})
export class AppComponent {   

  constructor() {
    Observable.interval(1000)
              .map((x) => x+1)
              .subscribe((x) => {
                this.message = x;
              }):
  }
}

但我希望约会一秒钟，直到达到0。

Answer 1

import { Component, NgOnInit, ElementRef, OnInit, OnDestroy } from 'angular2/core';
import { Observable, Subscription } from 'rxjs/Rx';

@Component({
    selector: 'my-app',
    template: `
  <div>
    {{message}}
  </div>
`
})
export class AppComponent implements OnInit, OnDestroy {

    private future: Date;
    private futureString: string;
    private counter$: Observable<number>;
    private subscription: Subscription;
    private message: string;

    constructor(elm: ElementRef) {
        this.futureString = elm.nativeElement.getAttribute('inputDate');
    }

    dhms(t) {
        var days, hours, minutes, seconds;
        days = Math.floor(t / 86400);
        t -= days * 86400;
        hours = Math.floor(t / 3600) % 24;
        t -= hours * 3600;
        minutes = Math.floor(t / 60) % 60;
        t -= minutes * 60;
        seconds = t % 60;

        return [
            days + 'd',
            hours + 'h',
            minutes + 'm',
            seconds + 's'
        ].join(' ');
    }


    ngOnInit() {
        this.future = new Date(this.futureString);
        this.counter$ = Observable.interval(1000).map((x) => {
           return Math.floor((this.future.getTime() - new Date().getTime()) / 1000);
        });

        this.subscription = this.counter$.subscribe((x) => this.message = this.dhms(x));
    }

    ngOnDestroy(): void {
        this.subscription.unsubscribe();
    }
}

HTML：

 <my-app inputDate="January 1, 2018 12:00:00">Loading...</my-app>

Answer 2

对Johnnyfittizio的回答做了一些修改。 https://stackoverflow.com/a/40784539/4579897

import {Observable} from 'rxjs/Rx';
import {Component, OnInit} from '@angular/core';

export class TimerComponent implements OnInit {

    private _trialEndsAt;
    private _diff: number;
    private _days: number;
    private _hours: number;
    private _minutes: number;
    private _seconds: number;

    constructor() {}

    ngOnInit() {  
        this._trialEndsAt = "2017-02-28";
        Observable.interval(1000).map((x) => {
            this._diff = Date.parse(this._trialEndsAt) - Date.parse(new Date().toString());
        }).subscribe((x) => {           
            this._days = this.getDays(this._diff);
            this._hours = this.getHours(this._diff);
            this._minutes = this.getMinutes(this._diff);
            this._seconds = this.getSeconds(this._diff);
        });
    }

    getDays(t){
        return Math.floor( t/(1000*60*60*24) );
    }

    getHours(t){
        return Math.floor( (t/(1000*60*60)) % 24 );
    }

    getMinutes(t){
        return Math.floor( (t/1000/60) % 60 );
    }

    getSeconds(t){
        return Math.floor( (t/1000) % 60 );
    }

}

Answer 3

这是一个带有硬编码日期的简化版本，并返回四个不同的输出（天 - 小时 - 分钟 - 秒），您可以很好地放在四个方框中：

export class HomePage {

    // Hardcoded date
    private eventDate: Date = new Date(2018, 9, 22);

    private diff: number;
    private countDownResult: number;
    private days: number;
    private hours: number;
    private minutes: number;
    private seconds: number;

    constructor(public navCtrl: NavController ) {

        Observable.interval(1000).map((x) => {
                this.diff = Math.floor((this.eventDate.getTime() - new Date().getTime()) / 1000);
            }).subscribe((x) => {           
                this.days = this.getDays(this.diff);
                this.hours = this.getHours(this.diff);
                this.minutes = this.getMinutes(this.diff);
                this.seconds = this.getSeconds(this.diff);
            });
    }

    getDays(t){
        var days;
        days = Math.floor(t / 86400);

        return days;
    }

    getHours(t){
        var days, hours;
        days = Math.floor(t / 86400);
        t -= days * 86400;
        hours = Math.floor(t / 3600) % 24;

        return hours;
    }

    getMinutes(t){
        var days, hours, minutes;
        days = Math.floor(t / 86400);
        t -= days * 86400;
        hours = Math.floor(t / 3600) % 24;
        t -= hours * 3600;
        minutes = Math.floor(t / 60) % 60;

        return minutes;
    }

    getSeconds(t){
        var days, hours, minutes, seconds;
        days = Math.floor(t / 86400);
        t -= days * 86400;
        hours = Math.floor(t / 3600) % 24;
        t -= hours * 3600;
        minutes = Math.floor(t / 60) % 60;
        t -= minutes * 60;
        seconds = t % 60;

        return seconds;
    }

}

Answer 4

我认为将定时器创建为服务更有意义，因此在创建视图时我可以更灵活（使用返回的Time模型，但是在组件中需要）。它会在订阅时创建一个新的可观察对象，以便每个订阅者获得自己的可观察性。简而言之，您可以根据需要使用此服务同时创建任意数量的计时器。请务必在AppModule提供程序的数组中包含此服务，以便在整个应用程序中使用它。

服务：

import { Injectable } from '@angular/core';
import {Observable} from 'rxjs/Observable';
import 'rxjs/add/observable/defer';
import 'rxjs/add/observable/interval';
import 'rxjs/add/operator/map';

export interface Time {
  days: number;
  hours: number;
  minutes: number;
  seconds: number;
}

@Injectable()
export class TimerService {

  constructor() { }

  private createTimeObject(date: Date): Time {

    const now = new Date().getTime();
    const distance = date.getTime() - now;

    let time: Time = {days: 0, hours: 0, minutes: 0, seconds: 0};
    time.days = Math.floor(distance / (1000 * 60 * 60 * 24));
    time.hours = Math.floor((distance % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60));
    time.minutes = Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60));
    time.seconds = Math.floor((distance % (1000 * 60)) / 1000);
    return time;
  }

  timer(date: Date): Observable<Time> {
      return Observable.interval(1000)
        .map(() => this.createTimeObject(date))
  }
}

现在在组件中使用它：

import {Component, OnInit} from '@angular/core';
import {Time, TimerService} from '../timer.service';

@Component({
  selector: 'app-timer',
  template: `
   <ng-container *ngIf="time1$ | async as time1"
     <pre>{{time1.days}}days {{time1.hours}}hours {{time1.minutes}} minutes {{time1.seconds}}seconds<pre>
     <br>
   <ng-container>

   <ng-container *ngIf="time2$ | async as time2"
     <pre>{{time2.days}}days {{time2.hours}}hours {{time2.minutes}} minutes {{time2.seconds}}seconds<pre>
     <br>
   <ng-container>
`
})
export class TimerComponent implements OnInit {

  time1$: Observable<Time>;
  time2$: Observable<Time>;

  constructor(private timerService: TimerService) {}

  ngOnInit() {

    this.time1$ = this.timerService.timer(new Date('June 4, 2020 15:37:25'))

    this.time2$ = this.timerService.timer(new Date('August 9, 2041 15:37:25'))

  }

Answer 5

为RXJS 5.5 +更新

import {map} from 'rxjs/internal/operators';
import { Component, OnInit } from '@angular/core';
import {interval, Observable} from 'rxjs';

@Component({
  selector: 'app-countdown',
  templateUrl: './countdown.component.html',
  styleUrls: ['./countdown.component.css']
})
export class CountdownComponent implements OnInit {

  private _trialEndsAt;

  private _diff: number;
  private _days: number;
  private _hours: number;

  private _minutes: number;

  private _seconds: number;

  constructor() {}

  ngOnInit() {

      this._trialEndsAt = "2017-02-28";

      interval(3000).pipe(
        map((x) => {this._diff = Date.parse(this._trialEndsAt) - Date.parse(new Date().toString());
          })).subscribe((x) => {
              this._days = this.getDays(this._diff);
              this._hours = this.getHours(this._diff);
              this._minutes = this.getMinutes(this._diff);
              this._seconds = this.getSeconds(this._diff);
          });
  }

  getDays(t) {
      return Math.floor( t / (1000 * 60 * 60 * 24) );
  }

  getHours(t) {
      return Math.floor( (t / (1000 * 60 * 60)) % 24 );
  }

  getMinutes(t) {
      return Math.floor( (t / 1000 / 60) % 60 );
  }

  getSeconds(t) {
      return Math.floor( (t / 1000) % 60 );
  }

}

Answer 6

这是我最近在我的项目中提出的解决方案。它检查事件的门打开时间和同一事件的主事件时间。这使用Momentjs。

我在onChanges函数中有代码，以防我的firebase中的事件时间发生变化，这是非常不可能的，但我喜欢它可以接收并动态更新的事实。

组件：

import { Component, OnInit, Input, OnChanges } from '@angular/core';
import { Observable } from "rxjs/Rx"
import { RoundService } from '../../round.service'
import * as moment from 'moment-timezone';

@Component({
  selector: 'race-countdown',
  templateUrl: './race-countdown.component.html',
  styleUrls: ['./race-countdown.component.scss']
})
export class RaceCountdownComponent implements OnChanges,OnInit{

    @Input() activeRound;

    public time:number;
    public timeToGates:number;
    public timeToMains:number;  
    public countDown:Observable<any>;
    public currentUnix = moment().unix();

    constructor(private rs:RoundService) { }

    ngOnChanges() {

    this.timeToGates = this.activeRound.gateOpenUnix - this.currentUnix;
    this.timeToMains = this.activeRound.mainEventUnix - this.currentUnix;

    if(this.timeToGates < 0)
        this.time = this.timeToMains
    else 
        this.time = this.timeToGates

  }

  ngOnInit() {

    this.countDown = Observable.interval(1000)
                                          .map(res=>{ return this.time = this.time-1 })
                                          .map(res=> {

                                            let timeLeft = moment.duration(res, 'seconds');
                                            let string:string = '';

                                            // Days.
                                            if(timeLeft.days() > 0) 
                                                string += timeLeft.days() + ' Days'

                                            // Hours.
                                            if(timeLeft.hours() > 0) 
                                                string += ' ' + timeLeft.hours() + ' Hours'

                                            // Minutes.
                                            if(timeLeft.minutes() > 0)
                                                string += ' ' + timeLeft.minutes() + ' Mins'

                                            // Seconds.
                                            string += ' ' + timeLeft.seconds(); 

                                            return string;

                                          })

  }

}

HTML：

<span>{{countDown | async}}</span>

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