I use PreloadJs to load the SpritSheet:
manifestLoad: any[] = [
{ "src": "spriteSheet.json",
"id": "spriteSheet-json",
"type": createjs.AbstractLoader.SPRITESHEET
}];
loadQueue.loadManifest(manifestLoad, true, Config.sPathGlobal);
For IOS APP we use the cordova-plugin-wkwebview-engine that implements the WKWebView component instead of the default UIWebView component.
However, you are still not able to use XHR from the file:// protocol.
I changed the parameter of LoadQueue to not use XHR, but some content requires XHR to work like JSON.