const array = [1, 1, 1, 3, 3, 2, 2]; // Method 1: Using a Set const unique = [...new Set(array)]; // Method 2: Array.prototype.reduce const unique = array.reduce((result, element) => { return result.includes(element) ? result : [...result, element]; }, []); // Method 3: Array.prototype.filter const unique = array.filter((element, index) => { return array.indexOf(element) === index; });