Node.js ships with a file system module allowing you to interact with files on the local hard disk. The file system module fs provides two methods allowing you to rename files: Fs#rename and Fs#renameSync.
This tutorial shows you how to rename a file synchronously and asynchronously using Node.js’ fs core module.
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Asynchronously Rename Files in Node.js
Node.js’ fs core module provides the Fs#rename method as an asynchronous/non-blocking way to rename files on disk. Non-blocking in this case means Node.js processes other operations while waiting for the hard disk to respond.
This rename supports callbacks by default. The callback support comes from the early days of Node.js where asynchronous operations were handled using callbacks.
Later, Node.js added support for promises and async/await. This tutorial assumes you’re using async/await for flow control of your code. That’s the reason the example uses the require('fs').promises exports available in Node.js v10.0.0 and later. These promise-based file system methods are usable with async/await.
The Fs#rename method expects two arguments:
- the old file path
- the new file path
At first, you may expect a file path and the new file name instead of two file paths as the arguments. Well, renaming a file is basically moving a file from one place to another. Even when not changing the directory. The underlying operation of renaming a file is the “move” from the previous name to the new one.
Here’s an example on how to rename a file in Node.js using the built-in fs module:
const Path = require('path')
const { promises: Fs } = require('fs')
const oldPath = Path.join(__dirname, "oldFile.txt")
const newPath = Path.join(__dirname, "newFile.txt")
await Fs.rename(oldPath, newPath)
Please notice: this method overwrites any existing file at newPath. In case the newPath points to an existing directory, this method throws an error.
Synchronously Rename Files
Node.js also comes with an Fs#renameSync method. This method blocks the Node.js event loop for other operations (because it waits for the hard disk) while renaming a file. Here’s an example showing you how to rename a file synchronously:
const Fs = require('fs')
const Path = require('path')
const oldPath = Path.join(__dirname, "oldFile.txt")
const newPath = Path.join(__dirname, "newFile.txt")
Fs.renameSync(oldPath, newPath)
Use the @supercharge/filesystem Package
I’m the maintainer of the @supercharge/filesystem package providing convenient file system utilities. Methods in the @supercharge/filesystem package are async by default and don’t block the event loop.
You may use the rename method supporting the same arguments as Node.js’ built-in method. In this case, the @supercharge/filesystem package just passes the calls through to Node.js’ core module without adding extra handling:
const Path = require('path')
const Fs = require('@supercharge/filesystem')
const oldPath = Path.join(__dirname, "oldFile.txt")
const newPath = Path.join(__dirname, "newFile.txt")
await Fs.rename(oldPath, newPath)
Enjoy!
Mentioned Resources
- Node.js docs for the fs module
- @supercharge/filesystem repository on GitHub