dedupe.js

Remove duplicate items from an array.

Works in all modern browsers, and at least back to IE9.

Demo on CodePen
How It Works

/*!
 * Remove duplicate items from an array
 * (c) 2019 Chris Ferdinandi, MIT License, https://gomakethings.com
 * @param  {Array} arr The array
 * @return {Array}     A new array with duplicates removed
 */
var dedupe = function (arr) {
	return arr.filter(function (item, index) {
		return arr.indexOf(item) === index;
	});
};