/**
 * Performs a GET HTTP request and optionally executes a callback
 *
 * @param url - URL of the JSON resource
 *
 * @param callback - an optional callback to execute after the request is successful. The response text is given as a parameter
 */
export function get(url: string, callback?: Function): void {
    const xhr = new XMLHttpRequest();
    xhr.onload = function (): void {
        if (this.status < 300 && this.status >= 200 && callback) {
            callback(xhr.responseText);
        }
    };
    xhr.open('GET', url, true);
    xhr.send();
}