@wezom/zz-load/dist/core.js

Lazy loader based on IntersectionObserver API

var __assign =
	(this && this.__assign) ||
	function () {
		__assign =
			Object.assign ||
			function (t) {
				for (var s, i = 1, n = arguments.length; i < n; i++) {
					s = arguments[i];
					for (var p in s)
						if (Object.prototype.hasOwnProperty.call(s, p)) t[p] = s[p];
				}
				return t;
			};
		return __assign.apply(this, arguments);
	};
import attrs from './config/attrs';
import events from './config/events';
import check from './utils/check';
import getElements from './utils/get-elements';
import markAs from './utils/mark-as';
import load from './loads';
// -----------------------------------------------------------------------------
// Private
// -----------------------------------------------------------------------------
var _defaultOptions = {
	rootMargin: '0px',
	threshold: 0,
	clearSourceAttrs: false,
	setSourcesOnlyOnLoad: true
};
// -----------------------------------------------------------------------------
// Public
// -----------------------------------------------------------------------------
export default function (elements, options) {
	if (options === void 0) {
		options = {};
	}
	var _options = __assign(__assign({}, _defaultOptions), options);
	var observer = null;
	if (window.IntersectionObserver) {
		observer = new window.IntersectionObserver(
			function (entries, observer) {
				entries.forEach(function (entry) {
					var element = entry.target;
					var inViewType = element.hasAttribute(attrs.sourceInview);
					if (entry.intersectionRatio > 0 || entry.isIntersecting) {
						if (inViewType) {
							markAs(element, attrs.inView, events.inView, {
								visible: true
							});
							load(element, _options);
						} else {
							observer.unobserve(element);
							load(element, _options);
						}
					} else {
						if (inViewType && check(element, attrs.inView)) {
							markAs(
								element,
								attrs.inView,
								events.inView,
								{ visible: false },
								true
							);
						}
					}
				});
			},
			{
				rootMargin: _options.rootMargin,
				threshold: _options.threshold
			}
		);
	}
	return {
		observe: function () {
			var list = getElements(elements);
			for (var i = 0; i < list.length; i++) {
				var element = list[i];
				if (check(element, attrs.observed)) {
					continue;
				}
				markAs(element, attrs.observed, events.observed);
				if (observer === null) {
					load(element, _options);
				} else {
					observer.observe(element);
				}
			}
		},
		triggerLoad: function (triggerElements, triggerOptions) {
			if (triggerOptions === void 0) {
				triggerOptions = {};
			}
			var list = getElements(elements);
			var loadOptions = __assign(__assign({}, _options), triggerOptions);
			for (var i = 0; i < list.length; i++) {
				var element = list[i];
				if (check(element, attrs.processed)) {
					continue;
				}
				markAs(element, attrs.observed, events.observed);
				load(element, loadOptions);
			}
		}
	};
}