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Remove duplicate items from an array.

Source Code


let sandwiches = ['turkey', 'ham', 'turkey', 'tuna', 'pb&j', 'ham', 'turkey', 'tuna'];

// returns ["turkey","ham","tuna","pb&j"]
let deduped = dedupe(sandwiches);

The helper function

 * Remove duplicate items from an array
 * (c) Chris Ferdinandi, MIT License,
 * @param  {Array} arr The array
 * @return {Array}     A new array with duplicates removed
function dedupe (arr) {
	return Array.from(new Set(arr));

How it works

The new Set() constructor creates an iterable collection of items, just like an array. But, each item can only be included once.

To remove any duplicates, we can pass our array into the new Set() constructor, then convert the returned collection back into an array.

let deduped = Array.from(new Set(sandwiches));