React Native验证码倒计时工具类分享

/**
 * Created by zhuang.haipeng on 2017.9.11
 *
 * 广告倒计时,验证码倒计时工具类
 *
 * 用法: //60 * 1000 为60秒 , 60 * 60 * 100 为60分钟 ...
 * let countdownDate = new Date(new Date().getTime() + 60 * 1000)
 *  CountdownUtil.settimer(countdownDate, (time) => {
 *   Console.log(time) --> {years: 0, days: 0, hours: 0, min: 0, sec: 49, millisec: 0}
 *  }
 *
 *  切记: 在应用工具类的页面退出的时候, 调用CountdownUtil.stop() 清除定时器,以免内存爆了
 */

export default class CountdownUtil {

  /** 定时器 */
  interval = null;

  /**
   * 创建定时器
   *
   */
  static settimer(countdownDate, callbak) {
    this.interval = setInterval(() => {
      let time = this.getDateData(countdownDate)
      callbak && callbak(time)
    }, 1000)
  }


  /**
   * 侄计时计算 --> 通过此方法计算,可以解决应用退出后台的时候,定时器不走
   * @param countdownDate
   * @return {*}
   */
  static getDateData(countdownDate) {
    let diff = (Date.parse(new Date(countdownDate)) - Date.parse(new Date)) / 1000;

    if (diff <= 0) {
     this.stop() // 倒计时为0的时候, 将计时器清除
      return 0;
    }

    const timeLeft = {
      years: 0,
      days: 0,
      hours: 0,
      min: 0,
      sec: 0,
      millisec: 0,
    };

    if (diff >= (365.25 * 86400)) {
      timeLeft.years = Math.floor(diff / (365.25 * 86400));
      diff -= timeLeft.years * 365.25 * 86400;
    }
    if (diff >= 86400) {
      timeLeft.days = Math.floor(diff / 86400);
      diff -= timeLeft.days * 86400;
    }
    if (diff >= 3600) {
      timeLeft.hours = Math.floor(diff / 3600);
      diff -= timeLeft.hours * 3600;
    }
    if (diff >= 60) {
      timeLeft.min = Math.floor(diff / 60);
      diff -= timeLeft.min * 60;
    }
    timeLeft.sec = diff;
    return timeLeft;
  }

  /**
   * 数字补零 --> 例: 00时01分59秒
   * @param num
   * @param length
   * @return {*}
   */
  static leadingZeros(num, length = null) {

    let length_ = length;
    let num_ = num;
    if (length_ === null) {
      length_ = 2;
    }
    num_ = String(num_);
    while (num_.length < length_) {
      num_ = '0' + num_;
    }
    return num_;
  }

  /** 清除定时器 */
  static stop() {
    clearInterval(this.interval);
  }
};