core/Common/js/desktop_fetch.js

// correct fetch for desktop application

var printErr = undefined;
var print    = undefined;

var fetch = ("undefined" !== typeof window) ? window.fetch : (("undefined" !== typeof self) ? self.fetch : null);
var getBinaryPromise = null;

function internal_isLocal()
{
	if (window.navigator && window.navigator.userAgent.toLowerCase().indexOf("ascdesktopeditor") < 0)
		return false;
	if (window.location && window.location.protocol == "file:")
		return true;
	if (window.document && window.document.currentScript && 0 == window.document.currentScript.src.indexOf("file:///"))
		return true;
	return false;
}

if (internal_isLocal())
{
	fetch = undefined; // fetch not support file:/// scheme
	getBinaryPromise = function()
	{
		var wasmPath = "ascdesktop://fonts/" + wasmBinaryFile.substr(8);
		return new Promise(function (resolve, reject)
		{
			var xhr = new XMLHttpRequest();
			xhr.open('GET', wasmPath, true);
			xhr.responseType = 'arraybuffer';

			if (xhr.overrideMimeType)
				xhr.overrideMimeType('text/plain; charset=x-user-defined');
			else
				xhr.setRequestHeader('Accept-Charset', 'x-user-defined');

			xhr.onload = function ()
			{
				if (this.status == 200)
					resolve(new Uint8Array(this.response));
			};
			xhr.send(null);
		});
	}
}
else
{
	getBinaryPromise = function() { return getBinaryPromise2.apply(undefined, arguments); }
}