ES6 Code Snippets

		const hide = (el) => [...el].forEach(e => (e.style.display = 'none'));
		
		// Example
		hide(document.querySelectorAll('img')); // Hides all  elements on the page
			

		const hasClass = (el, className) => el.classList.contains(className);
		
		// Example
		hasClass(document.querySelector('p.special'), 'special'); // true
		

		const toggleClass = (el, className) => el.classList.toggle(className);
		
		// Example
		toggleClass(document.querySelector('p.special'), 'special'); 
		// The paragraph will not have the 'special' class anymore
		

		const getScrollPosition = (el = window) => ({
			x: el.pageXOffset !== undefined ? el.pageXOffset : el.scrollLeft,
			y: el.pageYOffset !== undefined ? el.pageYOffset : el.scrollTop
		});
		
		// Example
		getScrollPosition(); // {x: 0, y: 200}
		

		const scrollToTop = () => {
			const c = document.documentElement.scrollTop || document.body.scrollTop;
			if (c > 0) {
				window.requestAnimationFrame(scrollToTop);
				window.scrollTo(0, c - c / 8);
			}
		};
		
		// Example
		scrollToTop();
		
		

		const elementContains = (parent, child) => parent !== child && parent.contains(child);
		
		// Examples
		elementContains(document.querySelector('head'), document.querySelector('title')); 
		// true
		elementContains(document.querySelector('body'), document.querySelector('body')); // false
		

		const elementIsVisibleInViewport = (el, partiallyVisible = false) => {
			const { top, left, bottom, right } = el.getBoundingClientRect();
			const { innerHeight, innerWidth } = window;
			return partiallyVisible
				? ((top > 0 && top < innerHeight) || (bottom > 0 && bottom < innerHeight)) &&
						((left > 0 && left < innerWidth) || (right > 0 && right < innerWidth))
				: top >= 0 && left >= 0 && bottom <= innerHeight && right <= innerWidth;
		};
		
		// Examples
		elementIsVisibleInViewport(el); // (not fully visible)
		elementIsVisibleInViewport(el, true); // (partially visible)
		

		const getImages = (el, includeDuplicates = false) => {
			const images = [...el.getElementsByTagName('img')].map(img => img.getAttribute('src'));
			return includeDuplicates ? images : [...new Set(images)];
		};
		
		// Examples
		getImages(document, true); // ['image1.jpg', 'image2.png', 'image1.png', '...']
		getImages(document, false); // ['image1.jpg', 'image2.png', '...']
		

		const detectDeviceType = () =>
			/Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent)
				? 'Mobile'
				: 'Desktop';
		
		// Example
		detectDeviceType(); // "Mobile" or "Desktop"
		

		const currentURL = () => window.location.href;
		
		// Example
		currentURL(); // 'https://google.com'
		

		const getURLParameters = url =>
			(url.match(/([^?=&]+)(=([^&]*))/g) || []).reduce(
				(a, v) => ((a[v.slice(0, v.indexOf('='))] = v.slice(v.indexOf('=') + 1)), a),
				{}
			);
		
		// Examples
		getURLParameters('http://url.com/page?n=Adam&s=Smith'); // {n: 'Adam', s: 'Smith'}
		getURLParameters('google.com'); // {}
		

		const formToObject = form =>
			Array.from(new FormData(form)).reduce(
				(acc, [key, value]) => ({
					...acc,
					[key]: value
				}),
				{}
			);
		
		// Example
		formToObject(document.querySelector('#form')); // { email: '[email protected]', name: 'Test Name' }
		

		const get = (from, ...selectors) =>
			[...selectors].map(s =>
				s
					.replace(/\[([^\[\]]*)\]/g, '.$1.')
					.split('.')
					.filter(t => t !== '')
					.reduce((prev, cur) => prev && prev[cur], from)
			);
		const obj = { selector: { to: { val: 'val to select' } }, target: [1, 2, { a: 'test' }] };
		
		// Example
		get(obj, 'selector.to.val', 'target[0]', 'target[2].a'); // ['val to select', 1, 'test']
		

		const delay = (fn, wait, ...args) => setTimeout(fn, wait, ...args);
		delay(
			function(text) {
				console.log(text);
			},
			1000,
			'later'
		); 
		
		// Logs 'later' after one second.
		

		const triggerEvent = (el, eventType, detail) =>
			el.dispatchEvent(new CustomEvent(eventType, { detail }));
		
		// Examples
		triggerEvent(document.getElementById('myId'), 'click');
		triggerEvent(document.getElementById('myId'), 'click', { username: 'bob' });
		

		const off = (el, evt, fn, opts = false) => el.removeEventListener(evt, fn, opts);
		
		const fn = () => console.log('!');
		document.body.addEventListener('click', fn);
		off(document.body, 'click', fn); // no longer logs '!' upon clicking on the page
		

		const formatDuration = ms => {
			if (ms < 0) ms = -ms;
			const time = {
				day: Math.floor(ms / 86400000),
				hour: Math.floor(ms / 3600000) % 24,
				minute: Math.floor(ms / 60000) % 60,
				second: Math.floor(ms / 1000) % 60,
				millisecond: Math.floor(ms) % 1000
			};
			return Object.entries(time)
				.filter(val => val[1] !== 0)
				.map(([key, val]) => `${val} ${key}${val !== 1 ? 's' : ''}`)
				.join(', ');
		};
		
		// Examples
		formatDuration(1001); // '1 second, 1 millisecond'
		formatDuration(34325055574); // '397 days, 6 hours, 44 minutes, 15 seconds, 574 milliseconds'
		

		const getDaysDiffBetweenDates = (dateInitial, dateFinal) =>
			(dateFinal - dateInitial) / (1000 * 3600 * 24);
		
		// Example
		getDaysDiffBetweenDates(new Date('2017-12-13'), new Date('2017-12-22')); // 9
		

		const httpGet = (url, callback, err = console.error) => {
			const request = new XMLHttpRequest();
			request.open('GET', url, true);
			request.onload = () => callback(request.responseText);
			request.onerror = () => err(request);
			request.send();
		};
		
		httpGet(
			'https://jsonplaceholder.typicode.com/posts/1',
			console.log
		); 
		
		// Logs: {"userId": 1, "id": 1, "title": "sample title", "body": "my text"}
		

		const httpPost = (url, data, callback, err = console.error) => {
			const request = new XMLHttpRequest();
			request.open('POST', url, true);
			request.setRequestHeader('Content-type', 'application/json; charset=utf-8');
			request.onload = () => callback(request.responseText);
			request.onerror = () => err(request);
			request.send(data);
		};
		
		const newPost = {
			userId: 1,
			id: 1337,
			title: 'Foo',
			body: 'bar bar bar'
		};
		const data = JSON.stringify(newPost);
		httpPost(
			'https://jsonplaceholder.typicode.com/posts',
			data,
			console.log
		); 
		
		// Logs: {"userId": 1, "id": 1337, "title": "Foo", "body": "bar bar bar"}
		

		const counter = (selector, start, end, step = 1, duration = 2000) => {
			let current = start,
				_step = (end - start) * step < 0 ? -step : step,
				timer = setInterval(() => {
					current += _step;
					document.querySelector(selector).innerHTML = current;
					if (current >= end) document.querySelector(selector).innerHTML = end;
					if (current >= end) clearInterval(timer);
				}, Math.abs(Math.floor(duration / (end - start))));
			return timer;
		};
		
		// Example
		counter('#my-id', 1, 1000, 5, 2000); // Creates a 2-second timer for the element with id="my-id"
		

		const copyToClipboard = str => {
			const el = document.createElement('textarea');
			el.value = str;
			el.setAttribute('readonly', '');
			el.style.position = 'absolute';
			el.style.left = '-9999px';
			document.body.appendChild(el);
			const selected =
				document.getSelection().rangeCount > 0 ? document.getSelection().getRangeAt(0) : false;
			el.select();
			document.execCommand('copy');
			document.body.removeChild(el);
			if (selected) {
				document.getSelection().removeAllRanges();
				document.getSelection().addRange(selected);
			}
		};
		
		// Example
		copyToClipboard('Lorem ipsum'); // 'Lorem ipsum' copied to clipboard.
		

		const isBrowserTabFocused = () => !document.hidden;
		
		// Example
		isBrowserTabFocused(); // true