The Buffer.readBigInt64LE() method in Node.js is used to read a 64-bits large integer from a specified offset from a buffer in
The Buffer.readBigInt64LE() method can be declared as shown in the code snippet below:
Buffer.readBigInt64LE(offset)
offset: The offset represents the number of bytes to skip before starting to read the buffer.
In other words, it is the index of the buffer.
- The
offsetvalue should be in the range 0 to (bufferLength-8).- The default value of
offsetis 0.
The Buffer.readBigInt64LE() method returns a 64-bit integer.
Consider the code snippet below that shows how the Buffer.readBigInt64LE() method is used.
const buff = Buffer.from([0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff]);console.log("buff stored in memory as", buff);console.log("Reading at offset 0:", buff.readBigInt64LE(0));
buff stored in memory as <Buffer 00 00 00 00 ff ff ff ff>
Reading at offset 0: -4294967296line 1: We declare a buffer, buff.
line 5: We use the Buffer.readBigInt64LE() method to get 64-bits from the 0 index in the little-endian format.
An index of the buffer is of 8 bits. In order to get 64 bits, we need to read 64/8 = 8 indices of the buffer.
The Buffer.readBigInt64LE() reads 8 indices of buff in little-endian format(buff read as 0xffffffff00000000) and returns a 64-bit number.