const names = ['John', 'Paul', 'George', 'Ringo', 'John']; let x = (names) => names.filter((v,i) => names.indexOf(v) === i) x(names); // 'John', 'Paul', 'George', 'Ringo'
var data = [1, 2, 'Peter', 3, 3,'Peter', 2, 2, 1, 2, 3, 4, 4, 5, 4]; var unique = data.filter((v, i, a) => a.indexOf(v) === i);