Basics
Arrays
Pop
The pop() method of Array instances removes the last element from an array and returns that element.
const plants = ['broccoli', 'cauliflower', 'cabbage', 'kale', 'tomato'];
console.log(plants.pop());
// Expected output: "tomato"
console.log(plants);
// Expected output: Array ["broccoli", "cauliflower", "cabbage", "kale"]
plants.pop();
console.log(plants);
// Expected output: Array ["broccoli", "cauliflower", "cabbage"]Push
The push() method of Array instances adds the specified elements to the end of an array and returns the new length of the array.
const animals = ['pigs', 'goats', 'sheep'];
const count = animals.push('cows');
console.log(count);
// Expected output: 4
console.log(animals);
// Expected output: Array ["pigs", "goats", "sheep", "cows"]
animals.push('chickens', 'cats', 'dogs');
console.log(animals);
// Expected output: Array ["pigs", "goats", "sheep", "cows", "chickens", "cats", "dogs"]
Unshift
The unshift() method of Array instances adds the specified elements to the beginning of an array and returns the new length of the array.
const array1 = [1, 2, 3];
console.log(array1.unshift(4, 5));
// Expected output: 5
console.log(array1);
// Expected output: Array [4, 5, 1, 2, 3]Shift
The shift() method of Array instances removes the first element from an array and returns that removed element.
const array1 = [1, 2, 3];
const firstElement = array1.shift();
console.log(array1);
// Expected output: Array [2, 3]
console.log(firstElement);
// Expected output: 1