What is fs.stat() in Node.js?
Node.js libraries provide a number of ways to interact with our file system and process them in several ways. We use Node’s fs, file system module, to manipulate files on our devices for this very purpose. We can create, read, update, rename, and delete files and directories with the fs module. We can also retrieve specific information about files and directories. For this purpose, the file system module provides the fs.stat() method. Let’s discuss how we can use fs.stat() with both callbacks and promises.
Note: To get started with the
fsmodule, we need to install Node.js first. Refer to the How to install Node JS on your system Answer for help with the installation.
The fs.stat method
The stat method in the fs module allows us to fetch details about any file regardless of the file type. All we need to do is specify the path leading to that file, and once the method loads the file details, a callback function will be returned. We’ll pass that callback function two arguments: first, an error message, and, second, an object containing the file stats.
Syntax
The following snippet shows the general syntax for using this method. There are two ways of using fs.stat(), one which returns a callback and the other which returns a promise.
fs.stat(file_path, options, call_back)
Let’s take a look at each parameter:
file_path: This is the path to the file or directory whose stats we require.options: To specify any optional arguments, we use theoptionsobject. The only argument that can be omitted from theoptionobject isbigint—it specifies whether numeric values returned byfs.stat()arebigint.call_back: As the name suggests, this is a callback function that executes afterfs.stat().
With callbacks
After reading the file, a callback is returned, passing the error message and file stats as arguments. The my_file_stats.size method returns the file’s size.
const fs = require("node:fs");const file_path = "my_file.txt"fs.stat( file_path, (error, my_file_stats) => {if (!error){console.log(my_file_stats.size);}else{console.error("Error occurred : ", error);}})
With promises
The following method will handle promises, but the rest of the procedures for retrieving file-related information will remain the same.
const fs = require("node:fs/promises");const file_path = "my_file.txt"async function retrieve_file_data(){try{const my_file_stats = await fs.stat(file_path)console.log(my_file_stats.size);}catch(error){console.error("Error occurred : ", error);}}retrieve_file_data()
Working example
The following example shows how to use the fs.stat() method. We’ll fetch the file details, like file size, and whether it is a file, directory, or symlink for three types of files: a text file, a spreadsheet, and an image file. Run the code below. Explore and make any desired changes.
hello educative users
Code explanation
Lines 1–2: First, we acquire the fs library for calling fs.stat() through simple callbacks or promises.
Lines 8–34: Then, we call the fs.stat() method in a way described in the callback section for both text and spreadsheet files. We just need to specify the file path leading to the text file. Lastly, we call the stats methods, namely:
my_text_file_stats.isFile(): This method checks whether the path given is of a file.my_text_file_stats.isDirectory(): TheisDirectory()method checks whether the specified path leads to a directory or not.my_text_file_stats.isSymbolicLink(): This method returns true if the path provided is that of a symbolic link.my_text_file_stats.size: This method returns the size of the file.
Lines 36–50: Using the promises way, we apply the fs.stat() method for an image file and a directory.
Conclusion
In conclusion, the fs.stat() method returns any file or directory-related information, whether the specified path is that of a file, directory, or symbolic link, and its size as well.
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