JS Capsules: Arrays

What's an Array?

An array is a data structure used to store a collection of elements in an ordered form.

let myArray = ["cheese", "milk", true, 8, "flamingo"];

An array can store elements of different data types - strings, numbers, booleans, objects, and even other arrays. The first element of an array always has an index 0.

To access specific elements in an array, you use bracket notation:

console.log(myArray[0]); // "cheese"
console.log(myArray[2]); // true

Forms of Array

The simplest form of an array is a linear array. It looks like this:

let linearArray = ["music",  13, "poetry", "prose", false, "edit"];

When an array contains other arrays, it is called a multi-dimensional array. It often looks like this:

let multiArray = ["bacon", ["nascar", "speed", 2], "water tank", false, 2];

A homogenous array contains elements of one data type:

let stringsArray = ["bed", "table", "phone", "laptop", "tv", "headset"];

A heterogenous array contains elements of different data types:

let mixedArray = [
    "Carl", 
    {homeAddress: "40 Grove street", city: "San Andreas"}, 
    [40, true, "seven"], 
    "clips", 
    24, 
    false
];

Common Array methods/properties

Array Methods

push(), unshift(), pop(), shift(), slice(), splice(), join(), sort(), map(), includes(), reduce(), indexOf(), forEach()

Array Properties

length, prototype, constructor