preload image as a promise #img #promise

fetchImage.js

/**
 * Returns a promise once an image has been preloaded successfully
 *
 * @param {String} url
 *
 * @returns {Promise}
 */
const fetchImage = (url) => new Promise((resolve, reject) => {

    const img = new Image();

    img.addEventListener('load', () => resolve(url), false);
    img.addEventListener('error', e => reject(e), false);
    img.setAttribute('src', url);

    if (img.complete) {
        resolve(url);
    }

});