Adding items

To add one or more items to the end of an array we can use push(). Note that you need to include one or more items that you want to add to the end of your array. 

const cities = ["Manchester", "Liverpool"];
cities.push("Cardiff");
console.log(cities); // [ "Manchester", "Liverpool", "Cardiff" ]
cities.push("Bradford", "Brighton");
console.log(cities); // [ "Manchester", "Liverpool", "Cardiff", "Bradford", "Brighton" ]

The new length of the array is returned when the method call completes. If you wanted to store the new array length in a variable, you could do something like this:

const cities = ["Manchester", "Liverpool"];
const newLength = cities.push("Bristol");
console.log(cities); // [ "Manchester", "Liverpool", "Bristol" ]
console.log(newLength); // 3

To add an item to the start of the array, use unshift():

const cities = ["Manchester", "Liverpool"];
cities.unshift("Edinburgh");
console.log(cities); // [ "Edinburgh", "Manchester", "Liverpool" ]