`Array.prototype.shift()`

Removes the first element from an array and returns it.

Syntax

arr.shift()

any — The removed first element, or undefined if the array is empty.

const a = [1, 2, 3];
console.log(a.shift(), a);

Output

1 [ 2, 3 ]

console.log([].shift());

Output

undefined

Mutates the array in place and re-indexes remaining elements (O(n)). Returns undefined for an empty array. Use `pop` to remove from the end.