Node.js Buffer.readUInt16BE() Method

The Buffer.readUInt16BE() method is an inbuilt application programming interface of class Buffer within the Buffer module which is used to read 16-bit value from an allocated buffer at a specified offset.

Syntax:

Buffer.readUInt16BE( offset )

Parameters: This method accepts single parameter offset that specifies the number of bytes to skip before read or simply signify the index in the buffer. The value of buffer lies 0 <= offset <= Buffer.length – 2. Its default value is 0.

Return Value: This method returns an unsigned 16-bit integer value that is read from buffer in big endian format (Buffer.readUInt16LE() read 16 bit in little endian format).

Below examples illustrate the use of Buffer.readUInt16BE() method in Node.js:

Example 1:

// Node.js program to demonstrate the  
// Buffer.readUInt16BE() method  

       
// Allocating buffer from array 
const buf = Buffer.from([0x21, 0x09, 0x19, 0x98]); 

  
// Printing allocated buffer 
console.log(buf); 

   
// Reading 16bits data from the buffer 
// and printing it as a string 
console.log(buf.readUInt16BE(0).toString(16)); 
console.log(buf.readUInt16BE(1).toString(16)); 
console.log(buf.readUInt16BE(2).toString(16)); 

Output:

<Buffer 21 09 19 98>
2109
919
1998

Example 2:

// Node.js program to demonstrate the  
// Buffer.readUInt16BE() method  

       
// Allocating buffer from array 
const buf = Buffer.from([0x21, 0x09, 0x19, 0x98]); 

  
// Printing allocated buffer 
console.log(buf); 

   
// Reading 16bits data from the buffer 
// and printing it as a string 
console.log(buf.readUInt16BE(0).toString(16)); 
console.log(buf.readUInt16LE(0).toString(16)); 
console.log(buf.readUInt16BE(1).toString(16)); 
console.log(buf.readUInt16LE(1).toString(16)); 
console.log(buf.readUInt16BE(2).toString(16)); 
console.log(buf.readUInt16LE(2).toString(16)); 

Output:

<Buffer 21 09 19 98>
2109
921
919
1909
1998
9819

Example 3:

// Node.js program to demonstrate the  
// Buffer.readUInt16BE() method  

       
// Allocating buffer from array 
const buf = Buffer.from([0x21, 0x09, 0x19, 0x98]); 

  
// Printing allocated buffer 
console.log(buf); 

   
// Reading 16bits data from the buffer 
// and printing it as a string 
console.log(buf.readUInt16BE(0).toString(16)); 
console.log(buf.readUInt16BE(1).toString(16)); 
console.log(buf.readUInt16BE(2).toString(16)); 

   
// Wrong index is provided to produce error 
console.log(buf.readUInt16BE(3).toString(16)); 

Output:

<Buffer 21 09 19 98>
2109
919
1998
internal/buffer.js:49
  throw new ERR_OUT_OF_RANGE(type || 'offset',
  ^
RangeError [ERR_OUT_OF_RANGE]: The value of "offset" is out of range.
It must be >= 0 and <= 2. Received 3
    at boundsError (internal/buffer.js:49:9)
    at Buffer.readUInt16BE (internal/buffer.js:215:5)
    . . .

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

Reference: https://nodejs.org/api/buffer.html#buffer_buf_readuint16be_offset

Article Tags :

Node.js

Web Technologies

Node.js-Buffer-module