CODEWITHSUNDEEP
angulartypescriptmomentjs
Tanzeel
Tanzeel

Reputation: 4998

How to get last day of a given month for a given year with moment

I'm working on an Angular project. I need last day of a given month for a given year using moment. But there are some limitations. I don't have a full date in a proper mm-dd-yyyy, etc format. And also that data types are any. We'll have two input fields, one for the month and the other for year. Then on click of Get last day button I should get the last day in numeric format, because I've to perform some arithmetic on that later. See it's very simple:

timeselector.component.html

<input [(ngModel)]="month"/>
<input [(ngModel)]="year"/>
<button (click)="getLastDate()">Get last date</button>

<p>Last date of {{month}}/{{year}} is: </p>

And this is what I want:

If month=12, year=1990; then lastDate should be 31

If month=11, year=2020; then lastDate should be 30

Care should be taken for leap years:

If month=2, year=2020; then lastDate should be 29

If month=2, year=2021; then lastDate should be 28

timeselector.component.ts

import { Component, DoCheck, OnInit } from '@angular/core';
import moment from 'moment';

@Component({
  selector: 'app-timeselector',
  templateUrl: './timeselector.component.html',
  styleUrls: ['./timeselector.component.css']
})
export class TimeselectorComponent {

  month=12;
  year=1990;

  lastDate="";

  getLastDate() {
  // logic to get last date of the given month NOT WORKING

  // const fromDate = moment(this.month, 'MM-DD-YYYY', true);
  // const toDate = moment(this.year, 'MM-DD-YYYY', true);
  // const customStartMonth = moment(fromDate, 'MM-DD-YYYY').month();
  // const customStartYear = moment(fromDate).year();
  // const customendMonth = moment(toDate, 'MM-DD-YYYY').month();
  // const customendYear = moment(toDate).year();

  }
}

I've tried many answers but they are different from mine. I've created a stackblitz also. Please help me. Is it even doable with moment or I'll have to write some custom code of my own. Please correct me.

Upvotes: 0

Views: 518

Answers (3)

Pranav C Balan
Pranav C Balan

Reputation: 115222

Get the first day of next month and then subtract 1 day from it.

let month = 2,
  year = 2020,
  lastDate = "";

var now = moment(`${month}/1/${year}`).add(1,'months').subtract(1, 'days');

alert(now);
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.2.1/moment.min.js"></script>

Upvotes: 2

Terry
Terry

Reputation: 577

Based on your demo : 

moment(this.year + '-' + this.month).endOf('month').format('DD')

Upvotes: 1

Dan Cantir
Dan Cantir

Reputation: 2955

A quick solution would be this:

const getLastDay = (year, month) => moment().year(year).month(month - 1).daysInMonth();

console.log(getLastDay(2020, 2));
console.log(getLastDay(2021, 2));
console.log(getLastDay(1990, 12));
console.log(getLastDay(2020, 11));
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.24.0/moment.min.js"></script>

Upvotes: 1

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