console.log([1, 2 ,3, 4, 5].map(item => item*2)); let arr1 = [1, 2, 3, 4, 5, 6, 7, 8]; let arr2 = [3, 1, 8]; let arr = arr1.filter(item => { return arr2.indexOf(item) === -1; }); console.log(arr);