React Native js常用时间日期处理方法

1.把2018-08-15 10:48:46转成date类

 /**
   * 可把- replace成/
   * @param dateString
   * @return Date
   */
 static parserDateString(dateString) {
    if (dateString) {
      const regEx = new RegExp('\\-', 'gi');
      const validDateStr = dateString.replace(regEx, '/');
      const milliseconds = Date.parse(validDateStr);
      return new Date(milliseconds);
    }
  }

2.根据当前的时间加上几年或者几天，常用于几年后或者几天后等处理

static addDataTime(thisTime,num,kind) {
    const newTime = new Date();
    if(kind =='year') {
      newTime.setFullYear(thisTime.getFullYear()+num);
    }else{
      newTime.setDate(thisTime.getDate()+num);
    }
    return newTime;
  }

3.比较时间大小，常用于开始时间不能大于结束时间等处理

static compareTime(startTime,endTime) {
    const startTimes = startTime.getTime();
    const endTimes = endTime.getTime();
    if(endTimes <= startTimes) {
      return false;
    }else{
      return true;
    }
  }

4. 时间转换成刚刚，几分钟前，几小时之前，几天前等，常用于展示记录消息评论时间等

 static dateToMsgTime(dataString) {
    const dateTime = DateUtil.parserDateString(dataString);
    const now = new Date();
    const nowTimeSpan = now.getTime();
    const oldTimeSpan = dateTime.getTime();
    let result = '';
    const milliseconds = nowTimeSpan-oldTimeSpan;
    if (milliseconds <= 1000 * 60 * 1) {
      result = '刚刚';
    }else if(1000 * 60 * 1 < milliseconds && milliseconds <= 1000 * 60 * 60) {
      result = `${Math.round((milliseconds / (1000 * 60)))}分钟前`;
    }else if(1000 * 60 * 60 * 1 < milliseconds && milliseconds <= 1000 * 60 * 60 * 24) {
      result = `${Math.round(milliseconds / (1000 * 60 * 60))}小时前`;
    }else if(1000 * 60 * 60 * 24 < milliseconds && milliseconds <= 1000 * 60 * 60 * 24 * 2) {
      result = `一天前${dataString.substr(11,5)}`;
    }else if(1000 * 60 * 60 * 24*2 < milliseconds && milliseconds <= 1000 * 60 * 60 * 24 * 3) {
      result = `两天前${dataString.substr(11,5)}`;
    }else{
      result = dataString.substr(0,10);
    }
    return result;
  }

5.日期转化成今天，昨天，日期等。输入格式为“2020-05-27”

 // 处理日期
    dealData = (data) => {
        if (data.length == 10) {
            let itemDate = Date.parse(new Date(data).toLocaleDateString()) / 1000;
            let curr = Date.parse(new Date()) / 1000;
            let rel = Math.floor(parseInt(curr - itemDate) / 60 / 60 / 24);
            if (rel == 0) {
                return "今天";
            } else if (rel == 1) {
                return "昨天"
            }
        }
        return data.substr(2).replace(/-/g, "/");
    };

6.计算过去了多少天

function howData(mdata){
   let d = new Date(mdata);
   let reduce = new Date().getTime()-d.getTime()
   return reduce/1000/3600/24 
}

howData("2019-07-24")
// 412.0910024189814