Node.js Buffer.slice() Method

Buffer is a temporary memory storage that stores the data when it is being moved from one place to another, it’s like an array of integers. 

The Buffer.slice() method returns a new Buffer that points to the same memory location as that of the input Buffer with only the cropped elements. 

Syntax:

buffer.slice( start, end )

Parameters: This method accepts two parameters as mentioned above and described below:

• start: It refers to the starting index from which the elements of the input buffer will be copied to the output buffer.
• end: It refers to the ending index till which the elements of the input buffer will be copied to the output buffer. (end index is not included in the count while slicing the buffer)

Return Value: It returns a buffer containing the altered buffer. 

Note: The default value of start and end indexes are 0 and buffer.length respectively. Negative indexes start from the end of the array.

The below examples illustrate the use of Buffer.slice() Method in Node.js:

Example 1: 

javascript

// Node program to demonstrate the
// Buffer.slice() method

// Creating a buffer
const buffer1 = new Buffer('GeeksForGeeks');

// Slicing a buffer
const output = buffer1.slice(8, 12);

// Converting the output buffer to string
console.log("Sliced Buffer is: " + output.toString());

Output: 

Sliced Buffer is: Geek

Example 2:

javascript

// Node program to demonstrate the
// Buffer.slice() method

const buffer = Buffer.from('Geek One');

const opBuffer = buffer.slice(0, 4) + " Two";

// Prints: Geek One
console.log(buffer.toString());

// Prints: Geek Two
console.log(opBuffer.toString());

Output:

Geek One
Geek Two

Note: The above program will compile and run by using the node fileName.js command. 

Reference: https://nodejs.org/api/buffer.html#buffer_buf_slice_start_end