Question

Is it possible to view the raw data for an image file in javascript?

I’m trying to write a script that converts an image into its hex dump.

How can I view the data I’m writing to the image file?

Answer 1

You can do this with XHR:

var xhr = new XMLHttpRequest();
xhr.open('GET', '/my/image/file.png', true);
xhr.responseType = 'arraybuffer'; // this will accept the response as an ArrayBuffer
xhr.onload = function(buffer) {
    var words = new Uint32Array(buffer),
        hex = '';
    for (var i = 0; i < words.length; i++) {
      hex += words.get(i).toString(16);  // this will convert it to a 4byte hex string
    }
    console.log(hex);
};
xhr.send();

Look at the doc for ArrayBuffers and TypedArrays

And you can see how I use it in testing here