ChocolateBird/data/html5_file_picker.js

var _snes_types = "application/vnd.nintendo.snes.rom,.sfc,.smc,.srm";
var _psx_types = "application/x-cd-image,application/x-iso9660-image,.bin,.iso";
var _gba_types = "application/x-gba-rom,.gba";
var _accepted_types = _snes_types+","+_psx_types+","+_gba_types;
var _FilePicker = {};
var _FilePickerData = {};
_FilePicker.upload = function(gd_callback) {
	// canceled = true;
	var input = document.createElement('INPUT');
	input.setAttribute("type", "file");
	input.setAttribute("accept", _accepted_types);
	input.setAttribute("multiple", "");
	input.click();
	input.addEventListener('change', event => {
		for (const file of event.target.files) {
			var reader = new FileReader();
			// this.filename = file.name;
			// this.file_type = file.type;
			reader.readAsArrayBuffer(file);
			reader.onloadend = (evt) => {
				if (evt.target.readyState == FileReader.DONE) {
					// Godot's JavaScriptObject API is very very poorly documented.
					// It might be possible to unwrap JavaScriptObject<ArrayBuffer> to PoolByteArray
					// without a bytewise for loop, but I can't work it out by trial and error.
					_FilePickerData[file.name] = evt.target.result;
					gd_callback(file.name, file.type);
				}
			}
		}
	});
}