Javascript：将时间戳转换为人类可读的日期？

Question

I'm simply trying to convert a timestamp back into a human readable date but what I get when converted is strange and wrong.

This is how I save the timestamp:

var timestamp = Number(new Date());
localStorag.setItem("mytimestamp", timestamp);

and this is how I get it back and convert it to readable date:

var mydate = localStorag.getItem("mytimestamp");
var jsDate = new Date(mydate*1000);

alert(jsDate);

The jsDate is wrong and I don't understand what's causing it!

Could someone please advise on this?

Answer 1

You can use the Number data type instead of date * 1000 to achieve this. See code example below:

// generate a timestamp
var timestamp = Number(new Date()) //1479895361931

Then

// get the date representation from the timestamp
var date = new Date(timestamp) // Wed Nov 23 2016 18:03:25 GMT+0800 (WITA)

Answer 2

Here is an easy solution using the toDateString() method:

const date = new Date(timestamp).toDateString();
console.log(date);

This will return something like: Thu Jul 14 2016

Answer 3

The cause of the issue here is when you multiply the timestamp by 1000.

If you simply pass myDate to the Date constructor you should get the correct time -

var timestamp = Number(new Date());
localStorage.setItem("mytimestamp", timestamp);
// ...
var mydateStr = localStorage.getItem("mytimestamp");
var myDate = Number(mydateStr); // convert the string back to a number
var jsDate = new Date(mydate);

It's true that Javascript deals with milliseconds but since you are generating the timestamp with Javascript and then reading it back also with Javascript, no conversion is needed - you can use the value as-is.

---

As was pointed out to me by @manish in the comments, the value stored in localStorage will be a string - remember to convert it back to a number before passing it to the Date constructor.

Answer 4

Try using moment.js . It add functions such as

moment().format('MMMM Do YYYY, h:mm:ss a'); // November 23rd 2016, 12:03:36 pm
moment().format('dddd');                    // Wednesday
moment().format("MMM Do YY");               // Nov 23rd 16
moment().format('YYYY [escaped] YYYY');     // 2016 escaped 2016
moment().format();                          // 2016-11-23T12:03:36+02:00

Answer 5

var yourTimestamp = localStorag.getItem("mytimestamp");
jsDate = new Date(yourTimestamp);

jsDateValues = [
   jsDate.getFullYear(),
   jsDate.getMonth()+1,
   jsDate.getDate(),
   jsDate.getHours(),
   jsDate.getMinutes(),
   jsDate.getSeconds(),
];
alert(jsDateValues); //=> [2011, 3, 25, 23, 0, 0]

and you can use the baove values and print in which format you wnat eg dd/mm/yyyy

Answer 6

The problem here is that when you store something in localstorage its being stored as string '1479895747557' and not a number So when you get the timestamp back from localstorage its not a number its a string. Though when you multiply it the value actually changes due to internal conversion it becomes 1479895747557000 and this represents a different date from the one you saved. So the solution would be to convert the string back to a number. Here is the code that works fine.

 var timestamp = Number(new Date()); localStorage.setItem("mytimestamp", timestamp); var mydate = localStorage.getItem("mytimestamp"); var jsDate = new Date(Number(mydate)); alert(jsDate);

Here is the code that does not performs the conversion back to number this will give you an Invalid Date.

 var timestamp = Number(new Date()); localStorage.setItem("mytimestamp", timestamp); var mydate = localStorage.getItem("mytimestamp"); var jsDate = new Date(mydate); alert(jsDate);

FIDDLE

Answer 7

By installing moment module in a nodejs project:

npm i --save moment

in a file.js file you can write:

const moment = require('moment');

let timestamp = Number(new Date());
let myMoment = moment(timestamp).format("MMMM Do YYYY_HH-mm-ss.SSSS"); // February 28th 2020_01-06-34.0000

Here the documentation of moment .