What is the best way to initialize a JavaScript Date to midnight?

What is the best way to initialize a JavaScript Date to midnight?

What is the simplest way to obtain an instance of new Date() but set the time at midnight?

Solutions/Answers:

Solution 1:

The setHours method can take optional minutes, seconds and ms arguments, for example:

var d = new Date();
d.setHours(0,0,0,0);

That will set the time to 00:00:00.000 of your current timezone, if you want to work in UTC time, you can use the setUTCHours method.

Solution 2:

Just wanted to clarify that the snippet from accepted answer gives the nearest midnight in the past:

var d = new Date();
d.setHours(0,0,0,0); // last midnight

If you want to get the nearest midnight in future, use the following code:

var d = new Date();
d.setHours(24,0,0,0); // next midnight

Solution 3:

A one-liner for object configs:

new Date(new Date().setHours(0,0,0,0));

When creating an element:

dateFieldConfig = {
      name: "mydate",
      value: new Date(new Date().setHours(0, 0, 0, 0)),
}

Solution 4:

Just going to add this here because I landed on this page looking for how to do this in moment.js and others may do too.

[Rationale: the word “moment” already appears elsewhere on this page so search engines direct here, and moment.js is widespread enough to warrant to being covered going on how often it is mentioned in other date-related SO questions]

So, in version 2.0.0 and above:

date.startOf('day');

For earlier versions:

date.sod();

Docs:

http://momentjs.com/docs/#/manipulating/start-of/

Solution 5:

You can probably use

new Date().setUTCHours(0,0,0,0)

if you need the value only once.

Solution 6:

Adding usefulness to @Dan’s example, I had the need to find the next midday or midnight.

var d = new Date();
if(d.getHours() < 12) {
   d.setHours(12,0,0,0); // next midnight/midday is midday
} else {
   d.setHours(24,0,0,0); // next midnight/midday is midnight
}

This allowed me to set a frequency cap for an event, only allowing it to happen once in the morning and once in the afternoon for any visitor to my site. The date captured was used to set the expiration of the cookie.