export function loadImage(imageUrl: string): Promise<string> {
    return new Promise(async (resolve, reject) => {
        const xhr = new XMLHttpRequest();

        xhr.responseType = 'arraybuffer';
        xhr.overrideMimeType('text/plain; charset=x-user-defined');

        xhr.addEventListener('error', reject, false);
        xhr.addEventListener(
            'load',
            async () => {
                if (xhr.status > 200) {
                    reject();
                    return;
                }
                const reader = new FileReader();
                const blob = new Blob([ xhr.response ]);
                reader.readAsDataURL(blob);

                reader.onloadend = () => {
                    resolve(`${ reader.result }`);
                };
            },
            false
        );

        xhr.open('GET', imageUrl, true);
        xhr.setRequestHeader('Cache-Control', 'max-age=604800, public');
        xhr.send(null);
    });
}