@wezom/zz-load/dist/loads/source-bg-img.js

Lazy loader based on IntersectionObserver API

export default function (element, resource, _a, loadActions, errorActions) {
	var setSourcesOnlyOnLoad = _a.setSourcesOnlyOnLoad;
	var setSourceImmediately = setSourcesOnlyOnLoad !== true;
	var img = document.createElement('img');
	img.addEventListener('error', function (event) {
		return errorActions(event, resource);
	});
	img.addEventListener('load', function (event) {
		if (setSourcesOnlyOnLoad) {
			element.style.backgroundImage = 'url(' + resource + ')';
		}
		loadActions(event, resource);
	});
	img.src = resource;
	if (setSourceImmediately) {
		element.style.backgroundImage = 'url(' + resource + ')';
	}
}