what does shift() do in js code example

Example 1: array shift javascript

//The shift() method removes the first element from an array 
//and returns that removed element. 
//This method changes the length of the array.

const array1 = [1, 2, 3];
const firstElement = array1.shift();
console.log(array1);
// expected output: Array [2, 3]
console.log(firstElement);
// expected output: 1

Example 2: javascript shift

let array = ["A", "B", "C"];

//Removes the first element of the array
array.shift();

//===========================
console.log(array);
//output =>
//["B", "C"]