The Buffer.writeBigInt64LE() method is an inbuilt application programming interface of class Buffer within the Buffer module which is used to write little-endian 64-bit Big integer value to an allocated buffer at the specified offset.
Syntax:
Buffer.writeBigInt64LE( value, offset )
Parameters: This method accepts two parameters as mentioned above and described below:
- value: This parameter specifies a big integer value to be written to the buffer. It should be a valid 64 bits little endian Big integer value. Behavior is undefined when the value is anything other than this.
- offset: It specifies the number of bytes to skip before writing or simply signify the index in the buffer. The value of offset lies 0 <= offset <= Buffer.length - 8. Its default value is 0.
Return Value: This method returns an integer value that is the sum of offset and number of bytes written.
The below examples illustrate the use of the Buffer.writeBigInt64LE() method in Node.js:
Example 1:
Filename: index.js
// Node.js program to demonstrate the
// buffer.writeBigInt64lE() method
const buf = Buffer.allocUnsafe(8);
// Writing big integer value into buffer
// by using writeBigInt64LE() method
buf.writeBigInt64LE(0x01030405060708n, 0);
// Display the buffer
console.log(buf);
Run the index.js file using the following command:
node index.js
Output:
<Buffer 08 07 06 05 04 03 01 00>
Example 2: Filename: index.js
// Node.js program to demonstrate the
// buffer.writeBigInt64lE() method
const buf = Buffer.allocUnsafe(8);
// Writing big integer value into buffer
// by using writeBigInt64LE() method
buf.writeBigInt64LE(0xaa03040506efffn, 0);
// Display the buffer
console.log(buf);
Run the index.js file using the following command:
node index.js
Output:
<Buffer ff ef 06 05 04 03 aa 00>
Reference: https://nodejs.org/dist/latest-v12.x/docs/api/buffer.html#buffer_buf_writebigint64le_value_offset