Array shift() in JavaScript – Mastering JS

Mar 1, 2022

The shift() function removes the first element from an array and returns the removed element.
As a result, the length of the array changes as well.

const array = [1, 2, 3, 4, 5];
array.shift(); 
array; 

If the array is empty, shift() will return undefined and not modify the array.

const array = [];
array.shift(); 

shift(), in combination with push(), can be used to make an array act like a queue as shown below.

const array = [];

function next(array) {
  return array.shift();
}

function enqueue(array, val) {
  array.push(val);
}

enqueue('First');
enqueue('Second');

next(); 
array; 
next(); 

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