Working with Files in NodeJS

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In NodeJS, the File System (FS) module provides an API to interact with the file system on your computer. This article will cover the basics of working with the FS module, including reading, writing, and manipulating files.

Importing the FS Module

To use the FS module, you'll need to import it into your Node.js script. You can do this using the require function:

const fs = require("fs");

Reading Files

To read a file, you can use the fs.readFile or fs.readFileSync functions. The former is asynchronous, while the latter is synchronous.

Asynchronous File Reading

fs.readFile("example.txt", "utf8", (err, data) => {
    if (err) {
        console.error("Error reading file:", err);
    } else {
        console.log("File content:", data);
    }
});

Synchronous File Reading

try {
    const data = fs.readFileSync("example.txt", "utf8");
    console.log("File content:", data);
} catch (err) {
    console.error("Error reading file:", err);
}

Writing Files

To write to a file, you can use the fs.writeFile or fs.writeFileSync functions. The former is asynchronous, while the latter is synchronous.

Asynchronous File Writing

const content = "This is a new text.";

fs.writeFile("example.txt", content, (err) => {
    if (err) {
        console.error("Error writing file:", err);
    } else {
        console.log("File written successfully.");
    }
});

Synchronous File Writing

const content = "This is a new text.";

try {
    fs.writeFileSync("example.txt", content);
    console.log("File written successfully.");
} catch (err) {
    console.error("Error writing file:", err);
}

Manipulating Files

The FS module also provides functions for manipulating files, like renaming and deleting them.

Renaming Files

fs.rename("oldName.txt", "newName.txt", (err) => {
    if (err) {
        console.error("Error renaming file:", err);
    } else {
        console.log("File renamed successfully.");
    }
});

Deleting Files

fs.unlink("example.txt", (err) => {
    if (err) {
        console.error("Error deleting file:", err);
    } else {
        console.log("File deleted successfully.");
    }
});

These are just the basics of working with the File System module in NodeJS. For more advanced use cases, you can refer to the official Node.js documentation.

FAQ

const fs = require("fs");

fs.readFile("example.txt", "utf8", (err, data) => {
    if (err) throw err;
    console.log(data);
});

const data = "Hello, World!";
fs.writeFile("example.txt", data, (err) => {
    if (err) throw err;
    console.log("The file has been saved!");
});

fs.unlink("example.txt", (err) => {
    if (err) throw err;
    console.log("The file has been deleted!");
});

const fileExists = fs.existsSync("example.txt");
console.log(fileExists ? "The file exists" : "The file does not exist");