CODEWITHSUNDEEP
javascript
Fatih Aktaş
Fatih Aktaş

Reputation: 1564

Why am I getting different Date results

Why am I getting different results from the Date objects below? I can't figure it out. Would you be able to explain what each of these corresponds to? Thanks!

console.log(new Date(Date.UTC(2019, 06, 27, 01, 41, 36)));
console.log(new Date(2019, 06, 27, 01, 41, 36));
console.log(new Date('2019-06-27T01:41:36'));

I am getting different days,

> Fri Jul 26 2019 19:41:36 GMT-0600 (Mountain Daylight Time)
> Sat Jul 27 2019 01:41:36 GMT-0600 (Mountain Daylight Time)
> Thu Jun 27 2019 01:41:36 GMT-0600 (Mountain Daylight Time)

The correct date seems to be the last one. How would I make the first two formats give the last one?

Upvotes: 0

Views: 79

Answers (2)

random
random

Reputation: 7891

const dt = new Date(Date.UTC(2019, 06, 27, 01, 41, 36));

// To display the date in UTC timezone use `toUTCString()`
// See - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/UTC
// Months start from index - 0
// 0 - Jan, 1-Feb, 2-Mar, 3-Apr, 4-May, 5-May, 6-Jun

console.log(dt.toUTCString());

// Individual date and time components are passed. 
// Month starts from index - 0
const dt1 = new Date(2019, 06, 27, 01, 41, 36);

console.log(dt1);

In new Date('2019-06-27T01:41:36'); date is passed in dateString, where month start from index - 1. See - https://www.rfc-editor.org/rfc/rfc2822#page-14, https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date

the numeric day-of-month MUST be between 1 and the number of days
allowed for the specified month

// The date is passed in dateString, where months start from index - 1

const dt2 = new Date('2019-06-27T01:41:36');
console.log(dt2);

Upvotes: 1

Bùi Đức Khánh
Bùi Đức Khánh

Reputation: 4518

3rd command

console.log(new Date('2019-06-27T01:41:36'));

Give you right result because It is ISO Dates https://www.w3schools.com/js/js_date_formats.asp

2nd command

console.log(new Date(2019, 06, 27, 01, 41, 36));

Give you result less than 1 month. Because in Date constructor JavaScript counts months from 0 to 11 (https://www.w3schools.com/js/js_dates.asp), so you need subtract month by 1 to receive right result

console.log(new Date(2019, 06 - 1, 27, 01, 41, 36));

1st command

console.log(new Date(Date.UTC(2019, 06, 27, 01, 41, 36)));

Reason for wrong month is the same with 2nd command, and UTC cause hour changed

Upvotes: 3

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