About time and date in Javascript

Get current date

**const** today **=** **new** Date();

The today object is a Date object, which is a built-in object in Javascript. You can convert it into string by using toString() method.

**const** today **=** **new** Date();
console.log(today.toISOString());
*// OUTPUT: 2023-06-13T13:56:25.031Z*console.log(today.toDateString());
*// OUTPUT: Tue Jun 13 2023*

Set a date

Set a date by string

**const** tomorrow **=** **new** Date('2023-06-14');
console.log(tomorrow.toDateString());
*// OUTPUT: Wed Jun 14 2023***const** wrongYesterday **=** **new** Date(23, 5, 12);
console.log(wrongYesterday.toDateString());
*// It will be 1923-06-12, not 2023-05-12, months are 0-based, years are 1900-based// OUTPUT: Fri Jun 12 1923***const** yesterday **=** **new** Date(2023, 5, 12);
console.log(yesterday.toDateString());
*// OUTPUT: Fri Jun 12 2023*

One can also pass in time to the Date constructor.

1. by string

   **const** tomorrow **=** **new** Date('2023-06-14T00:00:00');
   console.log(tomorrow.toDateString());
   *// OUTPUT: Wed Jun 14 2023*
   

2. by milliseconds number

   **const** aDay **=** **new** Date(1666342680472);
   console.log(aDay);
   *// OUTPUT: 2022-10-21T08:58:00.472Z*
   

   Note: this number is the milliseconds since 1970-01-01 00:00:00 UTC. Its called Unix Epoch.

Date calculation

**const** today **=** **new** Date();
**const** tomorrow **=** **new** Date(today);
tomorrow.setDate(today.getDate() **+** 1);
console.log(tomorrow.toDateString());
*// OUTPUT: Wed Jun 14 2023*

Date and Time comparison

Compare two dates

**const** today **=** **new** Date();
**const** tomorrow **=** **new** Date(today);
tomorrow.setDate(today.getDate() **+** 1);
console.log(today **<** tomorrow);
*// OUTPUT: true*

Compare two times

**const** today **=** **new** Date();
**const** aDay **=** **new** Date(1666342680472);
aDay.setDate(today.getDate() **+** 1);
console.log(today.getTime() **<** aDay.getTime());
*// OUTPUT: flase*

A simple function to get just date string

❗️ date.getMonth() will get month based from ZERO !