Getting wrong month in moment.js

Question

I'm using Moment.js included through RequireJS. When I call Moment().month(), instead of number 11 I always get number 10. Any ideas how can this happen?

Isn't [january month 0](http://momentjs.com/docs/#/get-set/month/)? `Note: Months are zero indexed, so January is month 0.` — Ron van der Heijden, Nov 20 '13 at 11:35
in javascript's Date, months are counted 0-11. http://www.w3schools.com/jsref/jsref_obj_date.asp — foibs, Nov 20 '13 at 11:36
You can always use the .add method to account for the zero index .add(1, 'M') — Jeremy Hamm, Jul 21 '16 at 21:28
@JeremyHamm That doesn't work for December. `moment.parseZone('12/01/2018','MM/DD/YYYY').add({M:1}).month()` — Belden, Apr 06 '18 at 16:26
Thank you @RenatoGama : it returns the correct month number, starting from one. — StøcciD, Aug 02 '22 at 15:34

score 76 · Accepted Answer · edited Mar 01 '23 at 08:34

76

According to Moment.js documentation, 'month' uses an array and the indices of an array are zero-based. Therefore, January is set to '0' and December is set to '11'.

For example, moment().month('November'); prints '10'.

edited Mar 01 '23 at 08:34

Graham John

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12

answered Nov 20 '13 at 11:41

Gnagy

1,432
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26

16

Just a clarification. 0-based indexing of the months is a feature that Moment.js inherits from Javascript. See the [ECMAScript specification](http://www.ecma-international.org/ecma-262/5.1/Ecma-262.pdf) at par.15.9.1.4 for further details. – Alberto De Caro Nov 20 '13 at 13:40
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Almost feels like they should expose it as 1-12 for the sake of intuitive use in lieu of the the ECMAScript specification. – Naruto Sempai Sep 26 '15 at 15:22
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by this logic why arent year, date, hours and minutes zero based?(snark, sorry) – Manuel Hernandez Apr 25 '16 at 05:17
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They actually claim month is not zero based: M MM 1..12 Month number – Andriy Kharchuk Jun 03 '19 at 04:17
working link to ECMAScript month spec: http://www.ecma-international.org/ecma-262/5.1/#sec-15.9.1.4 – haja Jan 28 '20 at 15:07
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We should create a dedicated web page that states the total dev time wasted by this. – Yaron Levi May 29 '20 at 16:40

score 1 · Answer 2 · answered Oct 05 '22 at 05:09

moment().month gets or sets the month and accepts numbers from 0 to 11. Key here is that index starts at 0, not 1. The below code will work as a solution for this question.

{Moment(yourDate).month(Moment(yourDate).month()-1).format("MMMM Do YYYY")}

The above code for 8/30/2022 will show August 30th 2022.

{Moment(yourDate).month(Moment(yourDate).month()-1).format("MM-DD-YYYY")}

The above code for 8/30/2022 will show 08-30-2022.

{Moment(yourDate).format("MM-DD-YYYY")}

The above code for 8/30/2022 will show 09-30-2022.

Getting wrong month in moment.js

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