Buffers in Node.js

Buffers in Node.js are used to store binary data directly in memory. They are very useful when working with files, streams, images, videos, or network data where normal strings are not enough.

• In simple words, a buffer is a temporary storage area that helps Node.js handle raw data efficiently

Methods of buffer module

Listed below are some common methods and properties of the Buffer module.

1. Using alloc() Method: It creates a Buffer object of the given length.

let buff = new Buffer.alloc(5);
console.log(buff);

Output:

2. equals() Method: It compares two buffer objects. Returns true if the object match else returns false.

let name1 = new Buffer.alloc(4, "Name");
let name2 = new Buffer.alloc(4, "Name");
console.log(new Buffer.from(name1).equals(name2));

Output:

3. copy() Method :It copies the given number of bytes of a buffer object.

let buff = new Buffer.alloc(5, "Geeks");
let name1 = new Buffer.alloc(5, "Name");
buff.copy(name1);
console.log(name1.toString());

Output:

4. length Property: Return the length of a buffer object in bytes.

let buff = new Buffer.alloc(5, 'ABCDE');
console.log(buff.length)

Output:

5. toString() Method: It returns a string form of a buffer object.

let name2 = new Buffer.alloc(3, "GFG");
console.log(name2);
console.log(name2.toString());

Output:

6. toJSON() Method: It returns a JSON form of a buffer object.

let myJson = new Buffer.alloc(10, { name: 'GFG' });
console.log(myJson.toJSON());

Output:

Creating a Buffer

In Node.js, buffers can be created using the Buffer class provided by the buffer module. Here are some common ways to create a buffer:

Creating a Buffer from a String

You can create a buffer from a string by specifying the encoding (default is utf-8).

const buffer = Buffer.from('Hello, World!', 'utf-8');
console.log(buffer); // <Buffer 48 65 6c 6c 6f 2c 20 57 6f 72 6c 64 21>

Creating an Uninitialized Buffer

To create a buffer of a specific size without initializing it, use the Buffer.allocUnsafe method. This is faster but might contain old data.

const buffer = Buffer.allocUnsafe(10);
console.log(buffer); // Uninitialized buffer with a size of 10

Creating an Initialized Buffer

Use Buffer.alloc to create a buffer and initialize it with zeroes.

const buffer = Buffer.alloc(10);
console.log(buffer); // Initialized buffer with a size of 10

Writing to a Buffer

You can write data to a buffer using the write method.

const buffer = Buffer.alloc(20);
buffer.write('Hello', 'utf-8');
console.log(buffer.toString('utf-8')); // Hello

Reading from a Buffer

You can read data from a buffer by converting it to a string or accessing its individual bytes.

const buffer = Buffer.from('Hello, World!', 'utf-8');
console.log(buffer.toString('utf-8')); // Hello, World!
console.log(buffer[0]); // 72 (ASCII code for 'H')