Get the Start and End of the Day using JavaScript

Get the Start and End of the Day using JavaScript #

Use the setUTCHours() method to get the start and end of the day, e.g. startOfDay.setUTCHours(0, 0, 0, 0). The method takes the hours, minutes, seconds and milliseconds as parameters and sets them for the specified date according to universal time.

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// ✅ In UTC (international time standard)
//          - keeps code consistent across time zones
const startOfDay = new Date();
startOfDay.setUTCHours(0, 0, 0, 0);
console.log(startOfDay);

const endOfDay = new Date();
endOfDay.setUTCHours(23, 59, 59, 999);
console.log(endOfDay);

// ✅ In Local Time (time zone the visitor's computer is in)
//             - will differ for users with different GEOs
const start = new Date();
start.setHours(0, 0, 0, 0);
console.log(start);

const end = new Date();
end.setHours(23, 59, 59, 999);
console.log(end);

We used the Date() constructor to get a date object that represents the current date and time.

In the first example, we used the setUTCHours method.

The method takes 4 parameters:

1. hoursValue - an integer between 0 and 23 that represents the hour.
2. minutesValue (optional) - an integer between 0 and 59 that represents the minutes.
3. secondsValue (optional) - an integer between 0 and 59 that represents the seconds.
4. msValue (optional) - a number between 0 and 999 that represents the milliseconds.

UTC (Coordinated Universal Time) and GMT share the same current time.

The difference between the two is that UTC is a time standard and GMT is a time zone.

UTC is an international time standard, which is used for consistency between time zones.

In the second example, we used the user's local time to get the start and end of the day. Local time refers to the time zone the visitor's computer is in.

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// ✅ In Local Time (time zone the visitor's computer is in)
//             - will differ for users with different GEOs
const start = new Date();
start.setHours(0, 0, 0, 0);
console.log(start);

const end = new Date();
end.setHours(23, 59, 59, 999);
console.log(end);

We used the setHours method instead of setUTCHours.

Depending on where the user visits your site from, this would yield different results.

The setUTCHours method does the same, but according to universal time.

For consistency, you should mostly use local time when you have to render a date and time to the user, but store the actual values in UTC.