Node.js Buffer.write() Method (original) (raw)

Last Updated : 12 Jul, 2025

The Buffer.write() method writes the specified string into a buffer, at the specified position. If buffer did not contain enough space to fit the entire string, only part of string will be written. However, partially encoded characters will not be written.Syntax:

buffer.write( string, offset, length, encoding )

Parameters: This method accept four parameters as mentioned above and described below:

• string: It holds the string to write into the buffer.
• offset: It holds the number of bytes to skip before starting to write the string. Its default value is 0.
• length: It holds the number of bytes to write into buffer. The default value is buffer.length-offset.
• encoding: It holds the encoding of the value. The default value is 'utf8'.

Return Value: This method returns a number that represents the number of bytes written.Example 1:

javascript `

// Node.js program to demonstrate the
// Buffer.write() method

// Create a buffer var buf = Buffer.from('GeeksforGeeks');

buf.write('EE', 1);

console.log(buf.toString());

`

Output:

GEEksforGeeks

Example 2:

javascript `

// Node.js program to demonstrate the
// Buffer.write() method

// Create a buffer const buf = Buffer.allocUnsafe(100);

const len = buf.write('GeeksforGeeks', 2, 5, 'utf8');

console.log(len.toString());

`

Output:

5

Note: The above program will compile and run by using the node index.js command.Reference: https://www.geeksforgeeks.org/node-js/node-js-buffer-allocunsafe-method/