What is the Buffer.writeBigUInt64LE() method Node.js?
The Buffer.writeBigUInt64LE() method
The Buffer.writeBigUInt64LE() method in Node.js is used to write 64-bits from a specified offset to a buffer in
Syntax
The Buffer.writeBigUInt64LE() method can be declared as shown in the code snippet below:
Buffer.writeBigUInt64LE(value, offset)
Parameters
-
value: A 64-bit unsigned integer to be written in the buffer. -
offset: The offset determines the number of bytes to skip before writing to the buffer.
In other words, it is the index of the buffer.
- The
offsetvalue should be greater than -1 and less than (bufferLength - 7).- The default value of
offsetis 0.
Return value
The Buffer.writeBigUInt64LE() method returns an integer whose value is offset + the number of bytes written to the buffer.
Code
Consider the code snippet below, it demonstrates how to use the Buffer.writeBigUInt64LE() method:
const buff = Buffer.allocUnsafe(8);buff.writeBigUInt64LE(0xabcdef1234567890n, 0);console.log(buff);
Output
<Buffer 90 78 56 34 12 ef cd ab>
Explanation
-
In line 1, we declare a buffer,
buff. -
The
writeBigUInt64LE()method is used in line 3 to write 64-bits from index 0 in the little-endian format.Since one index of the buffer is 8-bits, we need to write at 8 indices of
buff. -
The
writeBigUInt64LE()method writes at 8 indices ofbuffstarting from index0, i.e.,index = 0-index + 8 - 1 = 7.Since the code is in the little Endian format, index 7 is written before index 6, index 6 is written before index 5, and so on.
