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It is a short tutorial on comparing two date objects in Angular with examples.
- How do you create a Date object in Angular
- How to compare two dates in Angular
- Compare two dates without time in Angular
Let’s see the Date object how do you create it in
How do you create a Date object in Angular
The Date object creates in Angular like a Javascript object.
Date object can be created in the Angular component as seen below.
currentDate: Date = new Date(); // This creates an date object with current date
date1: Date = new Date('01.01.2020'); // This creates a date object with a given day month and year
Empty Date constructor prints the current date. A date with a valid string creates a date with a given date.
Let’s declare an angular component
import { Component, OnInit } from '@angular/core';
@Component({
selector: 'app-datecompare',
templateUrl: './datecompare.component.html',
styleUrls: ['./datecompare.component.css']
})
export class DatecompareComponent implements OnInit {
date1: Date = new Date('01.01.2020');
currentDate: Date = new Date();
}
How to compare date objects for equal in Angular
In Angular, any object can be compared using the relational operator (===)
In the same way, we can use the === operator to compare date objects.
Angular typescript component
import { Component, OnInit } from '@angular/core';
@Component({
selector: 'app-datecompare',
templateUrl: './datecompare.component.html',
styleUrls: ['./datecompare.component.css']
})
export class DatecompareComponent implements OnInit {
date1: Date = new Date();
date2: Date = new Date();
constructor() { }
ngOnInit(): void {
}
isDateEqual() {
if (this.date1.getTime() === this.date2.getTime())
return true;
return false;
}
}
In Typescript,
- function
isDateEqual()which checks for date comparison - First, create a
Dateobject in Angular using a new Date object for the current date. DirectlyDateobject can not be compared, Instead, we have to use theDate.getTimefunction and===operator.Date.getTime()returns a long number of milliseconds since 01-01-1979 UTC.
Template component
<p>Date object Comparision</p>
{{isDateEqual()}} // true
We can also use other relational operators such as <= and >=
How to compare the given Date with the current Date in Angular
Suppose the Date object is coming from Database, You want to compare it with the current date.
Below is an angular example to compare the given date before or after of current date.
We can use <,> !==,<=,>= relational operators for comparing dates.
import { Component, OnInit } from '@angular/core';
@Component({
selector: 'app-datecompare',
templateUrl: './datecompare.component.html',
styleUrls: ['./datecompare.component.css']
})
export class DateComponent implements OnInit {
date1: Date = new Date('01.01.2020');
currentDate: Date = new Date();
constructor() { }
ngOnInit(): void {
}
compareDates(){
if(this.date1.getTime()<this.currentDate.getTime()){
console.log("date1 is before current date")
}
if(this.date1.getTime()>this.currentDate.getTime()){
console.log("date1 is after current date")
}
}
}
How to compare future Date with current Date in a template component
Sometimes, We want to compare the Current date with future dates,
Here is an angular component to compare future dates with the given date.
import { Component, OnInit } from '@angular/core';
@Component({
selector: 'app-datecompare',
templateUrl: './datecompare.component.html',
styleUrls: ['./datecompare.component.css']
})
export class DateComponent implements OnInit {
futureDate: Date = new Date('01.01.2022');
currentDate: Date = new Date();
constructor() { }
ngOnInit(): void {
}
checkFutureDate(){
if(this.futureDate.getTime()>this.currentDate.getTime()){
console.log("date1 is before current date");
return true;
}
}
}
In Template component
using *ngIf directive, We can use the function to check truthy values
compare dates using the MomentJS library in Angular
First, install the momentJS library using the npm command.
npm install moment --save
In the Angular component, import below moment objects
import * as a moment from 'moment';
In angular component code, You can use the moment object like a normal object
Create a date object like this
date: moment.Moment=new moment("2020-06-01");
momentJS has isSame, isBefore, and isAfter functions to check future and past dates and equal
isSame: checks whether two-moment date objects are equal or not
moment('2021-02-12').isSame('2021-02-12'); // true
moment('2021-02-12').isSame('2021-02-15'); // false
moment('2021-02-12').isSame('2021-02-10'); // false
isBefore: One date is before another date
moment('2021-02-12').isBefore('2021-02-12'); // false
moment('2021-02-12').isBefore('2021-02-15'); // true
moment('2021-02-12').isBefore('2021-02-10'); // false
isAfter: one date is after another date
moment('2021-02-12').isAfter('2021-02-12'); // false
moment('2021-02-12').isAfter('2021-02-15'); // false
moment('2021-02-12').isAfter('2021-02-10'); // true
Can you compare dates in angular?
Dates objects are compared like a number.
- First Convert the string object into a Date object using the new Date(String) constructor
- next, find the number of milliseconds using date.getTime(), returns EPOCH timestamp
- Compare numbers of milliseconds using logical operators.
- Returns true if equal, false if it is not satisfied
Conclusion
In this tutorial, you learned different examples for comparing two dates that are equal and comparing future and given dates with the current date.
