The **``Buffer.copy``** function is used to copy the contents from one buffer object to another.
# Syntax
```
buffer1.copy(buffer2, paste_si, copy_si, copy_ei);
```

# Parameters
The illustration below describes four parameters that the ``Buffer.copy`` function takes:

# Return value
The ``Buffer.copy`` function returns the number of bytes copied from buffer1 to buffer2.

# Example
The code snippet below demonstrates how data elements can be copied from one buffer to the other. This program copies data from the *3rd* to *4th* index of `one_buffer` and pastes it at the *0th* index of `two_buffer`:
>Notice that data at the *5th* index in `one_buffer` was excluded.

var one_buffer = Buffer.from('000000');
var two_buffer = Buffer.from('111111111');

console.log("The buffer value from which we copy  is:", one_buffer.toString())
console.log("The buffer value to which we copy is:", two_buffer.toString())

one_buffer.copy(two_buffer, 0, 3, 5);

console.log("The new buffer is:", two_buffer.toString());

What is Buffer.copy in Node.js?

The `Buffer.copy` function in Node.js copies data between buffer objects, returning the bytes copied.