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

Last Updated : 3 May, 2023

The Buffer.writeUIntLE() method is used to write the specified bytes, using little endian, to a Buffer object. It supports up to 48 bits of accuracy. Its behavior is undefined when you use the value of anything other than an unsigned integer.

Syntax:

Buffer.writeUIntLE( value, offset, byteLength )

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

value: It specifies the number which needs to be written to the Buffer object.
offset: It specifies the number of bytes to skip before starting to write into the buffer. The value of offset lies 0 <= offset <= buf.length - byteLength.
byteLength: It specifies the number of bytes to write into the buffer. The value of byteLength lies 0 < byteLength <= 6.

Return value: It returns the offset plus the number of bytes written. The below examples illustrate the use of Buffer.writeUIntLE() Method in Node.js:

Example 1:

javascript `

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

// Creating a buffer of size 4 const buffer_1 = Buffer.allocUnsafe(4);

// Writes byteLength bytes of value to buf // at the specified offset. buffer_1.writeUIntLE(0x12127474, 0, 4);

// Display the result console.log(buffer_1);

// Creating a buffer of size 6 const buffer_2 = Buffer.allocUnsafe(6); buffer_2.writeUIntLE(0x12127474abcd, 0, 6);

// Display the result console.log(buffer_2);

Output:

Example 2:

javascript `

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

// Creating a buffer of given size const buffer = Buffer.allocUnsafe(8); //Before writing anything console.log("Before filling buffer"); console.log(buffer);

// to fill first 6 bytes, take offset 0 // and bytelength 6 console.log("After filling 6 bytes"); buffer.writeUIntLE(0xcc1267280012, 0, 6); console.log(buffer);

// to fill next 2 bytes add 6 offset // and bytelength 2 console.log("After filling next 2 bytes"); buffer.writeUIntLE(0x1112, 6, 2) console.log(buffer);

Output:

Before filling buffer <Buffer 00 00 00 00 00 00 00 00> After filling 6 bytes <Buffer 12 00 28 67 12 cc 00 00> After filling next 2 bytes <Buffer 12 00 28 67 12 cc 12 11>

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

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