Edit in JSFiddle

let items = [1, 2, 4, 5, 6];
let elementToDelete = 5; // element which is to be deleted

let newArray = items.filter(item => item !== elementToDelete);
console.log('newArray', newArray); // [ 1, 2, 4, 6 ] => 5 is not present in new array
console.log('original items', items); // [1, 2, 4, 5, 6] => original array is unaffected