async GET(String url) {
    var xhr = new XMLHttpRequest();
		    
    xhr.onreadystatechange() {
        if (xhr.readyState != 4) return;
        if (xhr.status == 200) resolve xhr.response;
		    	
        reject false;
    }
		    
    xhr.open("GET", url, true);
    xhr.send();
}

Object info = await GET("info.json");
console.log(info);