util.js

/**
 * TODO: Need to add error handling and then submit pull request to 'blob-util'
 *       library.
 */
export function objectURLToBlob(url) {
    return new Promise((resolve, reject) => {
        let xhr = new XMLHttpRequest();
        xhr.open('GET', url, true);
        xhr.responseType = 'blob';
        xhr.onreadystatechange = () => {
            if (xhr.DONE !== xhr.readyState) return;
            resolve(xhr.response);
        }
        xhr.send();
    });
}