How to get the File Extension of a File using Node

Because Node is a back-end language, it runs on the server and can perform file system operations.

A common operation is needing to know what the extension of a file is.

In this post, we'll learn how to get the file extension of a file on the file system using Node.

How to get the file extension of a file

Getting the file extension of a file is easy thanks to the built-in path module.

This module has the extname method that can be used to get the file extension of a file.

Simply pass it the path of a valid file and it will return the file extension.

JAVASCRIPT
import * as path from "path";

const ext = path.extname("/path/to/file.txt");

console.log(ext);

BASH
.txt

In case you have a file name with numerous dots, the extname method will return the file extension of the last dot.

JAVASCRIPT
import * as path from "path";

const ext = path.extname("/path/to/file.txt.zip");

console.log(ext);

BASH
.zip

Keep in mind that if the file has no extension, it will return a blank string:

JAVASCRIPT
import * as path from "path";

const ext = path.extname("/path/to/file");

console.log(ext);

BASH

Conclusion

In this post, we learned how to get the file extension of a file using Node.

Simply import the path module and use the extname method with a valid file path.

Thanks for reading and happy coding!

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