@wezom/zz-load/dist/utils/generate-sources.js

Lazy loader based on IntersectionObserver API

import dataset from '../config/data-set';
export default function (element) {
	var sourcesAttrs = JSON.parse(element.dataset[dataset.sourceSources] || 'null');
	if (Array.isArray(sourcesAttrs)) {
		return sourcesAttrs
			.filter(function (attrs) {
				return (
					typeof attrs === 'object' && attrs !== null && !Array.isArray(attrs)
				);
			})
			.map(function (attrs) {
				var source = document.createElement('source');
				for (var attr in attrs) {
					source.setAttribute(attr, attrs[attr]);
				}
				return source;
			});
	}
	return [];
}