Javascript - BYTES_PER_ELEMENT is undefined in Opera

Question

I'm trying to write some application using ArrayBuffers, Websockets and DataStream.js library, but it is failing on pretty simple code and I haven't found any related pages about same problem.

The problem is that

var arr = new Uint8Array(6);
alert(arr.BYTES_PER_ELEMENT);

Returns undefined. I can use directly Uint8Array.BYTES_PER_ELEMENT (which is in Opera 1), but DataStream.js library is using "universal" way to get this property: (DataStream.js:377)

DataStream.memcpy(arr.buffer, 0,
                this.buffer, this.byteOffset+this.position,
                length*arr.BYTES_PER_ELEMENT);

Is there some way to keep it universal but working in Opera 12? Something like arr.__proto__.BYTES_PER_ELEMENT.

Or am I doing something wrong? In Chromium it works OK.

Answer 1

So, after short discussion with ivy_lynx, I decided to do it this simple way, which sets value that should be set in prototypes. Now the DataStream.js library works OK even in Opera 12.16

if (Uint8Array.prototype.BYTES_PER_ELEMENT == undefined) {
    Uint8Array.prototype.BYTES_PER_ELEMENT = Uint8Array.BYTES_PER_ELEMENT; 
    Uint8ClampedArray.prototype.BYTES_PER_ELEMENT = Uint8ClampedArray.BYTES_PER_ELEMENT; 
    Int8Array.prototype.BYTES_PER_ELEMENT = Int8Array.BYTES_PER_ELEMENT; 
    Uint16Array.prototype.BYTES_PER_ELEMENT = Uint16Array.BYTES_PER_ELEMENT; 
    Int16Array.prototype.BYTES_PER_ELEMENT = Int16Array.BYTES_PER_ELEMENT; 
    Uint32Array.prototype.BYTES_PER_ELEMENT = Uint32Array.BYTES_PER_ELEMENT; 
    Int32Array.prototype.BYTES_PER_ELEMENT = Int32Array.BYTES_PER_ELEMENT; 
    Float64Array.prototype.BYTES_PER_ELEMENT = Float64Array.BYTES_PER_ELEMENT; 
}