const numbers = [3, 2, 1] const newFirstNumber = 4 // => [ 4, 3, 2, 1 ] [newFirstNumber].concat(numbers) // => [ 3, 2, 1, 4 ] numbers.concat(newFirstNumber)
if you want to avoid mutating your original array, you can use concat.
let cats = ['Bob']; // => ['Willy', 'Bob'] cats.unshift('Willy'); // => ['Puff', 'George', 'Willy', 'Bob'] cats.unshift('Puff', 'George');
Add items to the beginning and returns the new array length.
let cats = ['Bob', 'Willy', 'Mini']; cats.shift(); // ['Willy', 'Mini']
Remove an item from the beginning and returns the removed item.
const fruits = ["apple", "orange", "banana"]; const fruit = fruits.pop(); // 'banana' console.log(fruits); // ["apple", "orange"]
Remove an item from the end and returns the removed item.
// Adding a single element: const cart = ['apple', 'orange']; cart.push('pear'); // Adding multiple elements: const numbers = [1, 2]; numbers.push(3, 4, 5);
Add items to the end and returns the new array length.
push
pop
unshift
shift
// Accessing an array element const myArray = [100, 200, 300]; console.log(myArray[0]); // 100 console.log(myArray[1]); // 200
const numbers = [1, 2, 3, 4]; numbers.length // 4
const fruits = ["apple", "orange", "banana"]; // Different data types const data = [1, 'chicken', false];