1var arr = [1, 2, 3, 4];
2var theRemovedElement = arr.shift(); // theRemovedElement == 1
3console.log(arr); // [2, 3, 4]
1pop(): Remove an item from the end of an array.
2push(): Add items to the end of an array.
3shift(): Remove an item from the beginning of an array.
4unshift(): Add items to the beginning of an array.