Arrays in JavaScript
A small Task from RS School about arrays in JavaScript.
To store ordered sets of data, we use a special structure called an Array.
Creating an array
To create an empty array, you can use two syntax options:
let arr = new Array();
let arr = [];
Usually, the second option is preferred. You can also immediately define initial values inside the square brackets:
let girls = ["Elle", "Mia", "Eve"];
Array indexing starts from zero.
To access an element, use its index inside square brackets:
let girls = ["Eve", "Mia", "Elle"];
console.log(girls[0]); // Eve
console.log(girls[1]); // Mia
console.log(girls[2]); // Elle
You can replace an array element like this:
girls[2] = 'Anna';
// the array is now:
girls = ["Eve", "Mia", "Anna"]
And you can add a new item into an existing array:
girls[3] = 'Elle';
// now the array looks like:
girls = ["Eve", "Mia", "Anna", "Elle"]
To get the number of items in the array, use the .length property:
let girls = ["Eve", "Mia", "Elle"];
console.log(girls.length); // 3
To print the entire array, just use console.log:
let girls = ["Eve", "Mia", "Elle"];
console.log(girls); // Eve, Mia, Elle
Arrays can hold values of different types. Example:
// mixed types
let arr = ['Elle', { name: 'Mia' }, true, function() { alert('I miss you'); }];
// get the object at index 1 and log its property
console.log(arr[1].name); // Mia
// get the function at index 3 and call it
arr[3](); // I miss you