Buffer from ArrayBuffer with memory copy

Question

I'm switching from Node.js 8.X to Node.js 10.x and I'm getting some deprecated warnings on "new Buffer"

I have an arrayBuffer that I need to copy into a Buffer and my first version was like this:

const newBuffer = Buffer.from(myArrayBuffer)

But the arrayBuffer is not copied in this case ( https://nodejs.org/api/buffer.html#buffer_class_method_buffer_from_arraybuffer_byteoffset_length ) so my data was corrupted in some cases when I refer to the buffer in asychronous code

so I switched to :

const newBuffer = new Buffer(Buffer.from(myArrayBuffer))

it works, but I get a warning with Node.js 10.X

I made this , but not sure it's the best way to achieve this

const newBuffer = Buffer.alloc(myArrayBuffer.byteLength)
const abView = Buffer.from(myArrayBuffer)
abView.copy(newBuffer)

Answer 1

To be on the safe side, you could do a byte by byte copy using a plain old for loop:

var newBuffer = new Buffer.alloc(myArrayBuffer.byteLength)

for (var i = 0; i < myArrayBuffer.length; i++)
    newBuffer[i] = myArrayBuffer[i];

This way you are sure to be dealing with a new object and not just a view on the ArrayBuffer.