Node.js Buffer.swap64() Method

The Buffer.swap64() 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 64-bit numbers.

Syntax:

Buffer.swap64()

Parameters: This method does not accept any parameters.

Return value: It returns the reference to the buffer.

Error thrown: It throws ERR_INVALID_BUFFER_SIZE if length of buffer (buf.length) is not a multiple of 8.

Below examples illustrate the use of Buffer.swap64() Method in Node.js:

Example 1:

// Node.js program to demonstrate the  
// Buffer.swap64() 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.swap64() method 
buf.swap64(); 
      
// Display the result  
// after swap 
console.log(buf);  

Output:

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

Example 2: We will look at error thrown by this method

// Node.js program to demonstrate the  
// Buffer.swap64() method  
      
// Creating a buffer  
const buf = Buffer.from([0x0, 
         0x1, 0x2, 0x3, 0x4, 0x5]);  
  
// Display the buffer value 
// before swap  
console.log(buf);  
  
try { 
    // Using Buffer.swap64() method 
    // It will throw error 
    buf.swap64(); 
  
    // Display the result  
    // after swap 
    console.log(buf); 
} 
catch(e) { 
    console.log("Entering catch block"); 
  
    // Display error 
    console.log(e); 
} 

Output:

<Buffer 00 01 02 03 04 05>
Entering catch block
RangeError [ERR_INVALID_BUFFER_SIZE]: Buffer size must be a multiple of 64-bits
    at Buffer.swap64 (buffer.js:1059:11)
    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_swap64

Tags:

#Node.js-Buffer-module #Node.js #Web Technologies

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