Add this code to the custom JS field in elfsight. Also disable MooTools on pages with elfsight widgets.

(function () {
	var RESTORE_NATIVES = true;
	var WATCH_MS = 5000;

	var fnToString = Function.prototype.toString;
	var getOwnNames = Object.getOwnPropertyNames;
	var getDesc = Object.getOwnPropertyDescriptor;
	var defineProp = Object.defineProperty;

	function isNative(fn) {
		try {
			return /\{\s*\[native code\]\s*\}/.test(fnToString.call(fn));
		} catch (e) {
			return true;
		}
	}

	function targets() {
		var list = [
			Object,
			Array,
			String,
			Number,
			Boolean,
			Function,
			Date,
			RegExp,
			Error,
			typeof Element !== 'undefined' ? Element : null,
			typeof HTMLElement !== 'undefined' ? HTMLElement : null,
			typeof Node !== 'undefined' ? Node : null,
			typeof NodeList !== 'undefined' ? NodeList : null,
			typeof HTMLCollection !== 'undefined' ? HTMLCollection : null,
			typeof DocumentFragment !== 'undefined' ? DocumentFragment : null,
			typeof Document !== 'undefined' ? Document : null,
			typeof Window !== 'undefined' ? Window : null,
			typeof EventTarget !== 'undefined' ? EventTarget : null,
			typeof Event !== 'undefined' ? Event : null,
			typeof Text !== 'undefined' ? Text : null,
			typeof HTMLFormElement !== 'undefined' ? HTMLFormElement : null,
			typeof XMLHttpRequest !== 'undefined' ? XMLHttpRequest : null,
		];
		var out = [],
			i;
		for (i = 0; i < list.length; i++) {
			if (list[i] && list[i].prototype) out.push(list[i]);
		}
		return out;
	}

	function hideEnumerable() {
		targets().forEach(function (C) {
			var proto = C.prototype,
				keys,
				i,
				key,
				d;
			try {
				keys = getOwnNames(proto);
			} catch (e) {
				return;
			}

			for (i = 0; i < keys.length; i++) {
				key = keys[i];
				if (key === 'constructor') continue;

				try {
					d = getDesc(proto, key);
				} catch (e) {
					continue;
				}
				if (!d || !d.enumerable || !d.configurable) continue;

				d.enumerable = false;
				try {
					defineProp(proto, key, d);
				} catch (e) {}
			}
		});
	}

	var cleanFrame = null;

	function cleanRealm() {
		if (cleanFrame && cleanFrame.contentWindow) return cleanFrame.contentWindow;
		var host = document.body || document.documentElement;
		if (!host) return null;

		cleanFrame = document.createElement('iframe');
		cleanFrame.setAttribute('aria-hidden', 'true');
		cleanFrame.setAttribute('tabindex', '-1');
		cleanFrame.style.cssText =
			'position:absolute!important;width:0!important;height:0!important;' +
			'border:0!important;opacity:0!important;pointer-events:none!important;' +
			'left:-9999px!important;top:-9999px!important';
		host.appendChild(cleanFrame);
		return cleanFrame.contentWindow;
	}

	function restoreNatives() {
		var W = cleanRealm();
		if (!W) return;

		var specs = [
			['Object', false],
			['Array', true],
			['String', true],
			['Number', true],
			['Boolean', false],
			['Function', false],
			['Date', true],
			['RegExp', false],
			['JSON', true],
			['Math', true],
		];

		function fix(mineObj, cleanObj) {
			var keys, i, key;
			try {
				keys = getOwnNames(cleanObj);
			} catch (e) {
				return;
			}

			for (i = 0; i < keys.length; i++) {
				key = keys[i];
				if (key === 'constructor' || key === 'prototype') continue;

				try {
					var cd = getDesc(cleanObj, key);
					if (!cd || typeof cd.value !== 'function') continue;

					var md = getDesc(mineObj, key);
					if (!md || typeof md.value !== 'function') continue;
					if (isNative(md.value)) continue;
					if (!md.configurable && !md.writable) continue;

					defineProp(mineObj, key, {
						value: cd.value,
						writable: true,
						configurable: true,
						enumerable: false,
					});
				} catch (e) {}
			}
		}

		specs.forEach(function (spec) {
			var mine = window[spec[0]],
				clean = W[spec[0]];
			if (!mine || !clean) return;
			if (mine.prototype && clean.prototype)
				fix(mine.prototype, clean.prototype);
			if (spec[1]) fix(mine, clean);
		});
	}

	function onReady(fn) {
		if (document.readyState === 'loading') {
			document.addEventListener('DOMContentLoaded', fn, false);
		} else {
			fn();
		}
	}

	function watch() {
		var started = Date.now();

		if (typeof MutationObserver === 'function') {
			var mo = new MutationObserver(function (records) {
				for (var i = 0; i < records.length; i++) {
					var added = records[i].addedNodes;
					for (var j = 0; j < added.length; j++) {
						var tag = added[j].nodeName;
						if (tag === 'SCRIPT' || tag === 'IFRAME') {
							hideEnumerable();
							return;
						}
					}
				}
			});
			onReady(function () {
				try {
					mo.observe(document.documentElement, {
						childList: true,
						subtree: true,
					});
				} catch (e) {}
			});
			setTimeout(function () {
				try {
					mo.disconnect();
				} catch (e) {}
			}, WATCH_MS);
		}

		var tick = setInterval(function () {
			hideEnumerable();
			if (Date.now() - started > WATCH_MS) clearInterval(tick);
		}, 250);
	}

	hideEnumerable();
	if (RESTORE_NATIVES) onReady(restoreNatives);
	onReady(hideEnumerable);
	window.addEventListener('load', hideEnumerable, false);
	watch();
})();