[javascript] linuxtimestamp to UTC time format

Introduction

In JavaScript, a Linux timestamp represents the number of milliseconds that have elapsed since January 1, 1970, 00:00:00 UTC. Converting this timestamp to a more human-readable format such as UTC time is a common task in programming. In this blog post, we will explore how to convert a Linux timestamp to UTC time format in JavaScript.

Using JavaScript’s Date Object

One of the simplest ways to convert a Linux timestamp to UTC time in JavaScript is by using the built-in Date object. The Date object in JavaScript represents a specific moment in time, allowing us to easily convert timestamps to various formats.

Here is an example code snippet demonstrating how to convert a Linux timestamp to a UTC date string using the Date object:

const timestamp = 1630565420000; // Linux timestamp
const date = new Date(timestamp);
const utcDate = date.toUTCString();
console.log(utcDate);

In this code snippet, we first create a new Date object with the Linux timestamp as an argument. We then use the toUTCString method to convert the date object to a string representing the date in UTC time format. Finally, we log the UTC date string to the console.

The output of the above code would be something like:

Tue, 01 Sep 2021 17:03:40 GMT

Using the toUTCString Method

Another approach to convert a Linux timestamp to UTC time format is by using the toUTCString method available on the Date object. This method returns a string representing the date and time in UTC time format.

Here is an example code snippet demonstrating the usage of the toUTCString method to convert a Linux timestamp to UTC time:

const timestamp = 1630565420000; // Linux timestamp
const utcDate = new Date(timestamp).toUTCString();
console.log(utcDate);

In this code snippet, we directly call the toUTCString method on the Date object created with the Linux timestamp as an argument. This simplifies the conversion process into a single line of code.

The output of the above code would be similar to the previous example:

Tue, 01 Sep 2021 17:03:40 GMT

Using the toISOString Method

Alternatively, we can also use the toISOString method available on the Date object to convert a Linux timestamp to UTC time format. The toISOString method returns a string representing the date and time in ISO 8601 format, which includes the UTC time zone.

Here is an example code snippet demonstrating the usage of the toISOString method to convert a Linux timestamp to UTC time:

const timestamp = 1630565420000; // Linux timestamp
const isoDate = new Date(timestamp).toISOString();
console.log(isoDate);

In this code snippet, we create a new Date object with the Linux timestamp and then call the toISOString method to obtain a string representation of the date and time in UTC format.

The output of the above code would be something like:

2021-09-01T17:03:40.000Z

Conclusion

Converting a Linux timestamp to UTC time format in JavaScript is a straightforward process using the built-in Date object. By leveraging methods such as toUTCString or toISOString, we can easily obtain a human-readable representation of the UTC time corresponding to a given timestamp. Whether you prefer a more traditional date string or an ISO 8601 format, JavaScript provides the necessary tools to handle timestamp conversions efficiently.