Java Script - Filter Unique Values - Arrays


The Set object type was introduced in ES6, and along with ..., the 'spread' operator, we can use it to create a new array with only the unique values.


const array = [1, 1, 2, 3, 5, 5, 1]

const uniqueArray = [...new Set(array)];

 

console.log(uniqueArray); // Result: [1, 2, 3, 5]


Before ES6, isolating unique values would involve a lot more code than that!


This trick works for arrays containing primitive types: undefined, null, boolean, string and number. (If you had an array containing objects, functions or additional arrays, you'd need a different approach!)

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