Node.js Buffer.readDoubleBE() Method

The Buffer.readDoubleBE() Method in Node.js is used to read a 64-bit double from the buffer at the given offset with the Big Endian format.

Syntax:

Buffer.readDoubleBE( offset )

Parameters: This method accepts single parameter offset which holds the number of bytes to skip before starting to read. The value of offset lies between 0 <= offset <= buf.length – 8. Its default value is 0.

Return Value: It returns an integer value in big endian format.

Below examples illustrate the use of buf.readDoubleBE() Method in Node.js:

Example 1:

// Node program to demonstrate the
// Buffer.readDoubleBE() method

// Creating a buffer of given size
const buf = Buffer.from([10, 20, 30, 40, 50, 60, 70, 80]);

// Display the result
console.log("Functions of Buffer.readDoubleBe(int)");
console.log(buf.readDoubleBE(0))
console.log(buf);

Output:

Functions of Buffer.readDoubleBe(int)
4.0888790063059496e-260
<Buffer 0a 14 1e 28 32 3c 46 50>

Example 2:

// Node program to demonstrate the
// Buffer.readDoubleBE() method

// Creating a buffer of given size
const buf = Buffer.from([100, 200, 300, 400, 500, 600, 700, 800]);

// Display the result
console.log("Functions of Buffer.readDoubleBe(int)");
console.log(buf.readDoubleBE(5))
console.log(buf);

Output:

Functions of Buffer.readDoubleBe(int)
internal/buffer.js:72
  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 <= 0. Received 5
   . . .

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

Reference: https://nodejs.org/docs/latest-v11.x/api/buffer.html#buffer_buf_readdoublebe_offset