Converting byte[] to ArrayBuffer in Nashorn

Question

How do I convert an array of bytes into ArrayBuffer in Nashorn? I am trying to insert binary data into a pure JavaScript environment (i.e., it doesn't have access to Java.from or Java.to) and so would like to create an instance out an array of bytes.

Answer 1

Looks like I was going about this the wrong way. It made more sense to convert it into Uint8Array since what I'm sending in is an array of bytes.

I created the following function:

function byteToUint8Array(byteArray) {
    var uint8Array = new Uint8Array(byteArray.length);
    for(var i = 0; i < uint8Array.length; i++) {
        uint8Array[i] = byteArray[i];
    }

    return uint8Array;
}

This will convert an array of bytes (so byteArray is actually of type byte[]) into a Uint8Array.

Answer 2

I think you're right about using a Uint8Array, but this code might be preferable:

function byteToUint8Array(byteArray) {
    var uint8Array = new Uint8Array(byteArray.length);
    uint8Array.set(Java.from(byteArray));
    return uint8Array;
}

Also, if you really need an ArrayBuffer you can use uint8Array.buffer.