Node.js Buffer.swap32() Method

The Buffer.swap32() method is an inbuilt application programming interface of class Buffer within Buffer module which is used to swap the buffer byte order in-place. The swapping is performed by interpreting buffer as an array of 32-bit numbers.

Syntax:

Buffer.swap32()

Parameters: This method does not accept any parameters.

Return value: It returns a reference to the swapped buffer.

Error thrown: It throws ERR_INVALID_BUFFER_SIZE if length of buffer (buf.length) is not a multiple of 4.

Below examples illustrate the use of Buffer.swap32() Method in Node.js:

Example 1:

// Node.js program to demonstrate the
// Buffer.swap32() method

// Creating a buffer
const buf = Buffer.from([0x7, 0x0,
        0x1, 0x1, 0x4, 0x5, 0x4, 0x6]);

// Display the buffer value
// before swap
console.log(buf);

// Using Buffer.swap32() method
buf.swap32();

// Display the result
// after swap
console.log(buf);

Output:

<Buffer 07 00 01 01 04 05 04 06>
<Buffer 01 01 00 07 06 04 05 04>

Example 2: This example display the error thrown by this method.

// Node.js program to demonstrate the
// Buffer.swap32() method

// Creating a buffer
const buf = Buffer.from([0x0, 0x1]);

// Display the buffer value
// before swap
console.log(buf);

try {
    // Using Buffer.swap32() method
    // It will throw error
    buf.swap32();

    // Display the result
    // after swap
    console.log(buf);

}
catch(e) {
    console.log("Entering catch block");

    // Display error
    console.log(e);
}

Output:

<Buffer 00 01>
Entering catch block
RangeError [ERR_INVALID_BUFFER_SIZE]: Buffer size
must be a multiple of 32-bits
    at Buffer.swap32 (buffer.js:1042:11)
    at /home/runner/index.js:14:9
    ......

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

Reference: https://nodejs.org/dist/latest-v13.x/docs/api/buffer.html#buffer_buf_swap32