Node.js日期比较

Question

在Node.js中，如果日期之一是字符串，如何将日期与今天的日期进行比较？

var retdate = new Date(); 
retdate.setDate(retdate.getDate()-7); 
var mydate = '2016-07-26T09:29:05.000Z' 

如何比较'retdate'和'mydate'，以便返回日期早于7天的日期？我相信字符串需要修改？

Answer 1

使用时刻JS只添加该模块到您的依赖

var moment = require('moment'); 

retdate = moment(retdate).format('YYYY-MM-DD'); 
mydate = moment(mydate).format('YYYY-MM-DD'); 

Answer 2

更新的解决方案：

由于OP是要求一个基于标准的JavaScript API的解决方案。

您可以做的是，由于您的日期字符串符合ISO-8601日期格式，因此您可以通过将日期字符串传递给构造函数来创建Date对象。

一旦你得到了2 Date对象，你可以直接从对象中减去，给你epoch日期时间。因此，您只需要用一周（7天）内的总毫秒数来分红，以确定日期A是否比日期B早。

例子：

var retdate = new Date(); 
 
retdate.setDate(retdate.getDate()-7); 
 
var mydatestring = '2016-07-26T09:29:05.00'; 
 
var mydate = new Date(mydatestring); 
 

 
var difference = retdate - mydate; // difference in milliseconds 
 

 
const TOTAL_MILLISECONDS_IN_A_WEEK = 1000 * 60 * 24 * 7; 
 

 
if (Math.floor(difference/TOTAL_MILLISECONDS_IN_A_WEEK) >= 7) { 
 
    console.log("Current date is more than 7 days older than : " + mydatestring); 
 
}

MomentJS解决方案：

像 'Newbee开发' 说MomentJS是解决各种日期相关的一个很好的JS日期时间模块问题。

首先使用moment(...)构造函数解析您的日期时间字符串，然后使用diff(...,'days') API进行日期比较。

例子：

var datetime = '2016-07-26T09:29:05.000Z'; 
 
var localTime = moment(); 
 
var otherTime = moment(datetime); 
 

 
console.log("Current datetime is older than " + datetime + " by 7 days = " + (localTime.diff(otherTime, 'days') >= 7));

<script src="http://momentjs.com/downloads/moment.js"></script>

见： http://momentjs.com/

Answer 3

您可以转换日期为毫秒，做数学，并将其转换回标准的日期。

//Today's date 
 
const today = new Date() 
 
    //Six days before today 
 
const sixDaysAgo = new Date(+(new Date()) - 6 * 24 * 60 * 60 * 1000) 
 
    //Seven days before today 
 
const sevenDaysAgo = new Date(+(new Date()) - 7 * 24 * 60 * 60 * 1000) 
 
    //One year ago 
 
const oneYearAgo = new Date(+(new Date()) - 365 * 24 * 60 * 60 * 1000) 
 
    //Given date from a date string 
 
const givenDate = new Date("2016-07-26T09:29:05.000Z") 
 

 
//Convert the range of days to milliseconds 
 
//(This wont work if the date very old) 
 
const sevenDaysInMiliSec = 7 * 24 * 60 * 60 * 1000 
 

 
var dateToValidate = sevenDaysAgo; 
 

 
if (today - dateToValidate >= sevenDaysInMiliSec) { 
 
    console.log(dateToValidate + " is seven days older or more") 
 
} else { 
 
    console.log(dateToValidate + " is less than seven days old") 
 
} 
 

 
dateToValidate = sixDaysAgo; 
 

 
if (today - dateToValidate >= sevenDaysInMiliSec) { 
 
    console.log(dateToValidate + " is seven days older or more") 
 
} else { 
 
    console.log(dateToValidate + " is less than seven days old") 
 
} 
 

 
dateToValidate = oneYearAgo; 
 

 
if (today - dateToValidate >= sevenDaysInMiliSec) { 
 
    console.log(dateToValidate + " is seven days older or more") 
 
} else { 
 
    console.log(dateToValidate + " is less than seven days old") 
 
} 
 

 
dateToValidate = givenDate; 
 

 
if (today - dateToValidate >= sevenDaysInMiliSec) { 
 
    console.log(dateToValidate + " is seven days older or more") 
 
} else { 
 
    console.log(dateToValidate + " is less than seven days old") 
 
}