我们通常在做秒杀活动时，会有活动开始或者活动结束倒计时
而在活动列表中，需要做统一处理
以下为做的关于倒计时的组件~

primaryColor可忽略，是关于倒计时时间的主题色
startTime活动开始时间
endTime活动结束时间
refresh方法为其中一个倒计时结束后，页面的重新渲染方法，经常是重新请求列表接口，方法自定义

组件文件

import React, { Component, CSSProperties } from 'react';
import { View } from '@tarojs/components';
import { isFunction } from 'lodash-es';
import { hexToRgba, iosTimeStringFomat } from '@/application/utils/format';
import './index.scss';

interface PaymentRewardCountdownProps {
  primaryColor: string;
  startTime: string;
  endTime: string;
  refresh(): void;
}
interface PaymentRewardCountdownState {
  timeRemaining: TimeRemaining | null;
}
interface TimeRemaining {
  type: 'start' | 'end' | 'ended';
  value: number;
}

export default class PaymentRewardCountdown extends Component<
  PaymentRewardCountdownProps,
  PaymentRewardCountdownState
> {
  constructor(props: PaymentRewardCountdownProps) {
    super(props);
    this.state = {
      timeRemaining: null
    };
  }

  componentDidMount(): void {
    const { startTime, endTime, refresh } = this.props;
    const iosStartTime = iosTimeStringFomat(startTime);
    const iosEndTime = iosTimeStringFomat(endTime);
    this.timer = setInterval(() => {
      const now = new Date();
      const start = new Date(iosStartTime);
      const end = new Date(iosTimeStringFomat(iosEndTime));

      if (now < start) {
        const diff = start.getTime() - now.getTime();
        this.setState({ timeRemaining: { type: 'start', value: diff } });
      } else if (now < end) {
        const diff = end.getTime() - now.getTime();
        this.setState({ timeRemaining: { type: 'end', value: diff } });
      } else {
        this.setState({ timeRemaining: { type: 'ended', value: 0 } });
        clearInterval(this.timer);
        if (isFunction(refresh)) {
          refresh();
        }
      }
    }, 1000);
  }

  componentWillUnmount() {
    if (this.timer) {
      clearInterval(this.timer);
    }
  }

  private timer: NodeJS.Timeout;

  private renderCountdown = () => {
    const { primaryColor } = this.props;
    const { timeRemaining } = this.state;
    if (!timeRemaining) {
      return null;
    }
    const numberStyle: CSSProperties = {
      color: primaryColor,
      background: `${hexToRgba(primaryColor, 0.5)}`
    };
    const timeInfo = formatSeconds(timeRemaining.value / 1000);
    return (
      <View className={classes.right}>
        <View className={classes.prefix}>
          {timeRemaining.type === 'start' ? '距离开始' : '距离结束:'}：
        </View>
        <View className={classes.number} style={numberStyle}>
          {timeInfo.days}
        </View>
        <View className={classes.symbol}>天</View>
        <View className={classes.number} style={numberStyle}>
          {timeInfo.hours}
        </View>
        <View className={classes.symbol}>时</View>
        <View className={classes.number} style={numberStyle}>
          {timeInfo.minutes}
        </View>
        <View className={classes.symbol}>分</View>
        <View className={classes.number} style={numberStyle}>
          {timeInfo.seconds}
        </View>
        <View className={classes.symbol}>秒</View>
      </View>
    );
  };

  render() {
    return <View className={prefix}>{this.renderCountdown()}</View>;
  }
}

const prefix = 'payment-reward-countdown';
const classes = {
  right: `${prefix}__right`,
  prefix: `${prefix}__right__prefix`,
  number: `${prefix}__right__number`,
  symbol: `${prefix}__right__symbol`
};
interface DataInfo {
  days: number;
  hours: string;
  minutes: string;
  seconds: string;
}
function addLeadingZero(num: number): string {
  if (num < 10) {
    return `0${num}`;
  }
  return num.toString();
}
function formatSeconds(time: number): DataInfo {
  const days = Math.floor(time / (3600 * 24));
  const hours = addLeadingZero(Math.floor((time % (3600 * 24)) / 3600));
  const minutes = addLeadingZero(Math.floor((time % 3600) / 60));
  const seconds = addLeadingZero(Math.floor(time % 60));

  return {
    days,
    hours,
    minutes,
    seconds
  };
}

样式文件

.payment-reward-countdown {
  display: flex;
  flex-direction: row;
  align-items: center;
  justify-content: space-between;
  &__right {
    height: 32px;
    display: flex;
    flex-direction: row;
    align-items: center;
    justify-content: flex-end;
    &__prefix {
      font-size: $font-size-mini;
    }
    &__number {
      padding: 0 6px;
      height: 32px;
      font-weight: 500;
      font-size: 22px;
      color: #FF3B30;
      line-height: 32px;
      text-align: center;
      background: rgba(255,59,48,0.05);
      border-radius: 4px;
    }
    &__symbol {
      padding: 0 6px;
      color: #666666;
      line-height: 28px;
      text-align: center;
      font-size: 20px;
      font-weight: bold;
    }
  }
}

在数组的item文件中，直接调用时间组件

<PaymentRewardCountdown
   startTime={market.startTime}
   endTime={market.endTime}
   refresh={this.refresh}
   primaryColor={primaryColor}
 />

示例图