How to get 30 days prior to current date?

I have a start calendar input box and an end calendar input box. We want defaults start calendar input box 30 days prior to current date and the end calendar input box to be the current date. Here is my date vars.

var today = new Date(),
dd    = today.getDate(),
mm    = today.getMonth(),
yyyy  = today.getFullYear(),
month = ["January", "February", "March",
"April", "May", "June", "July", "August",
"September", "October" "November", "December"],
startdate = month[mm] + ", " + yyyy.toString();

The end date would be something like var enddate = startdate - 30; Obviously this won't work.

So if the current date is December 30, 2011 I'd want the start date to read December 1, 2011.

EDIT: My question was answered... sort of. Date.today(); and Date.today().add(-30); work but I need the date in the format of January 13, 2012. Not Fri Jan 13 2012 10:48:56 GMT -055 (EST). Any help?

MORE EDIT: As of this writing it's 2018. Just use Moment.js. It's the best.

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I use date.js. It handles this easily and takes care of all the leap-year nastiness.

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最佳答案

Try using the excellent Datejs JavaScript date library (the original is no longer maintained so you may be interested in this actively maintained fork instead):

Date.today().add(-30).days(); // or...
Date.today().add({days:-30});

[Edit]

See also the excellent Moment.js JavaScript date library:

moment().subtract(30, 'days'); // or...
moment().add(-30, 'days');
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startDate = new Date(today.getTime() - 30*24*60*60*1000);

The .getTime() method returns a standard JS timestamp (milliseconds since Jan 1/1970) on which you can use regular math operations, which can be fed back to the Date object directly.

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To subtract days from a JS Date object you can use the setDate() method, along with the date to start the calculation from. This will return an epoch timestamp as an integer, so to convert this to a Date you'll need to again provide it to the Date() object constructor. The final example would look like this:

var today = new Date();
var priorDate = new Date(new Date().setDate(today.getDate() - 30));


console.log(today)
console.log(priorDate);

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I will prefer moment js

startDate = moment().subtract(30, 'days').format('LL')  // January 29, 2015


endDate = moment().format('LL'); // February 28, 2015
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Here's an ugly solution for you:

var date = new Date(new Date().setDate(new Date().getDate() - 30));
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Easy.(Using Vanilla JS)

let days=30;
this.maxDateTime = new Date(Date.now() - days * 24 * 60 * 60 * 1000);

ISOFormat ?

let days=30;
this.maxDateTime = new Date(Date.now() - days * 24 * 60 * 60 * 1000).toISOString();
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Javascript can handle it without any external libraries. 

var today = new Date();
var dateLimit = new Date(new Date().setDate(today.getDate() - 30));


document.write(today + "<br/>" + dateLimit)

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This is an ES6 version

let date = new Date()
let newDate = new Date(date.setDate(date.getDate()-30))
console.log(newDate.getMonth()+1 + '/' + newDate.getDate() + '/' + newDate.getFullYear() )
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You can do that simply through 1 line of code using moment in Node JS. :)

    let lastOneMonthDate = moment().subtract(30,"days").utc().toISOString()

Don't want UTC format, EASIER :P

    let lastOneMonthDate = moment().subtract(30,"days").toISOString()
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Get next 30th day from today

let now = new Date()
console.log('Today: ' + now.toUTCString())
let next30days = new Date(now.setDate(now.getDate() + 30))
console.log('Next 30th day: ' + next30days.toUTCString())

Get last 30th day form today

let now = new Date()
console.log('Today: ' + now.toUTCString())
let last30days = new Date(now.setDate(now.getDate() - 30))
console.log('Last 30th day: ' + last30days.toUTCString())

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If you aren't inclined to momentjs, you can use this:

let x = new Date()

x.toISOString(x.setDate(x.getDate())).slice(0, 10)

Basically it gets the current date (numeric value of date of current month) and then sets the value. Then it converts into ISO format from which I slice down the pure numeric date (i.e. 2019-09-23)

Hope it helps someone.

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let today = new Date()

let last30Days = new Date(today.getFullYear(), today.getMonth(), today.getDate() - 30)

last30Days will be in Date Object

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Simple 1 liner Vanilla Javascript code :

const priorByDays = new Date(Date.now() - days * 24 * 60 * 60 * 1000)

For example: days = 7 Assume current date = Fri Sep 18 2020 01:33:26 GMT+0530

The result would be : Fri Sep 11 2020 01:34:03 GMT+0530

The beauty of this is you can manipulate it to get result in desired type

  • timestamp : Date.now() - days * 24 * 60 * 60 * 1000

  • ISOString: new Date(Date.now() - 7 * 24 * 60 * 60 * 1000).toISOString()

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Use moment.js

let startDate =  moment().subtract(30, "days").format('YYYY-MM-DD'); //2021-05-18
let endDate = moment().format('YYYY-MM-DD'); //2021-06-17
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For anyone looking for the format 'dd month yyyy', here's what worked for me:

let date = new Date()


let newDate = new Date(date.setDate(date.getDate()-30))


console.log(newDate.getDate()+ ' ' +newDate.toLocaleString('default', {month: 'long'}) + ' ' + newDate.getFullYear() )

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