Introduction
In programming, we regularly must take care of dates and occasions, which will be represented in a couple of alternative ways, like an object (through Date), a string (i.e. “2023-10-04T00:00:00.000Z”), or a timestamp (i.e. 1696377600000). On this Byte, we’ll discover the right way to convert a date or date string to a timestamp in JavaScript.
Why Convert Date or Date String to Timestamp
However why do we have to convert a date or date string to a timestamp within the first place? Timestamps are a extra common manner of storing date and time data. They characterize the variety of seconds (or milliseconds) because the Unix Epoch (January 1, 1970), making them a easy solution to retailer date and time knowledge. They’re additionally timezone-agnostic, which may simplify issues when coping with knowledge from completely different time zones.
Dates and Timestamps in JavaScript
Earlier than we get into changing our dates, let’s take a second to grasp what we’re coping with. In JavaScript, a Date object represents a second in time. You may create a brand new Date object with the new Date() constructor.
Alternatively, a timestamp is a numeric illustration of a date, as described earlier.
let currentDate = new Date();
console.log(currentDate); // Outputs: 2023-10-04T13:20:23.670Z
Easy methods to Convert a Date to Timestamp
Changing a Date object to a timestamp in JavaScript is fairly simple. You need to use the getTime() technique, which returns the variety of milliseconds because the Unix Epoch.
let currentDate = new Date();
let timestamp = currentDate.getTime();
console.log(timestamp); // Outputs: 1696425660603
Be aware: The getTime() technique returns the timestamp in milliseconds. In case you want the timestamp in seconds, you possibly can divide the consequence by 1000.
Easy methods to Convert a Date String to Timestamp
So what if we have now a date in string format? It will be an analogous course of as earlier than, however with the additional step of changing the string to a Date object after which the timestamp.
Simply be sure that your date string is in a format that the Date constructor can perceive. In accordance with MDN:
The JavaScript specification solely specifies one format to be universally supported: the date time string format, a simplification of the ISO 8601 calendar date prolonged format. The format is as follows:
YYYY-MM-DDTHH:mm:ss.sssZ
Apparently different codecs do work, however are implementation-dependent and should not work throughout all browsers.
let dateString = "2023-10-04";
let dateObject = new Date(dateString);
let timestamp = dateObject.getTime();
console.log(timestamp); // Outputs: 1696377600000
So the date string needs to be in a format acknowledged by the Date.parse() technique (used internally by the Date constructor). Whereas the above format is formally specified, you may as well use extra shorthand dates like “YYYY-MM-DD”.
Different Options
Whereas we have targeted on the Date object and its getTime() technique for changing a date to a timestamp in JavaScript, there are different methods to realize the identical factor. As an illustration, the valueOf() technique returns the primitive worth of a Date object as a quantity knowledge sort, which is the timestamp.
This is an instance:
let date = new Date();
console.log(date.valueOf()); // Output: 1696428432208
The + operator can be used to transform a Date object to a timestamp. This works as a result of the + operator triggers the valueOf() technique behind the scenes to be able to do any mathematical operation on the date.
let date = new Date();
console.log(+date); // Output: 1696428432208
Be aware: Whereas these strategies obtain the identical consequence, it is necessary to grasp how they work and when to make use of them. The + operator, for instance, is likely to be much less clear to somebody studying your code than the express getTime() or valueOf() strategies.
Frequent Errors and Easy methods to Keep away from Them
A typical mistake when working with dates and timestamps in JavaScript is just not accounting for time zones. JavaScript’s Date object is based mostly on the consumer’s native time zone, however timestamps are at all times UTC. This will result in surprising outcomes if not dealt with appropriately.
For instance, as an example you create a Date object for midnight on a particular date:
let date = new Date('2023-10-04T00:00:00');
console.log(date.getTime()); // Output: 1696428432208
Relying in your native time zone, the timestamp won’t characterize midnight UTC, however another time. To keep away from this, at all times create Date objects in UTC while you plan to transform them to timestamps.
One other frequent mistake is utilizing the Date.parse() technique to transform a date string to a timestamp. Whereas this could work, it isn’t really helpful as a result of Date.parse() has inconsistent conduct throughout completely different browsers and may result in some very hard-to-find bugs!
Use-Circumstances of Date/Timestamp Conversion
Changing dates to timestamps is helpful in lots of conditions. For instance, timestamps are sometimes utilized in APIs and databases to file when an occasion occurred. By storing the time as a timestamp, you possibly can simply evaluate occasions and calculate durations—one thing that is a lot more durable, or extra error-prone, with date strings.
Timestamps are additionally helpful for efficiency testing. By taking a timestamp at the beginning and finish of a course of, you possibly can calculate how lengthy it took. This can be a frequent approach in JavaScript and different programming languages. You’d do that by creating new Date objects at the beginning/finish of the method, however then you definately’d must convert to timestamp to have the ability to discover the distinction between the 2.
Conclusion
On this Byte, we have realized the right way to convert a date to a timestamp in JavaScript utilizing the Date object’s getTime() technique. We have additionally checked out various strategies, frequent errors to keep away from, and a few use-cases for date and timestamp conversion.
