07 Arrays

07_01 Arrays Explained

We use arrays when we want to group some items together or because we need to apply some sort of order to a bunch of objects or a whole array. We use arrays a lot in programming to store, retrieve and process data.
There are a whole set of array functions and methods which help us to work with and manipulate these arrays. We see methods which helps us in adding/removing objects, find objects, reorder objects etc. In JS these methods have names like pop, push and shift among others.
pop removes the last element, push inserts the element into array, to remove from index 0 and move all the items after this we shift the elements one position to left, to add element on first index we move items to right emptying up the index 0 thus, callingthis unshift.

An array is an instance of the array object and we declare a new array by creating a variable and [] to tell the js that it’s an array.
In JS we can also add element by skipping some index as well. E.g. your list has 4 items but you do collection[9] = "In the end" now this will be added to the list and this means if you do collection[9] you will get what you have stored and index from 4 to 8 will return undefined as those indices were just skipped and have nothing in the list.
Ref: 07_02

Arrays are used extensively in JS. There is a whole set of array methods to do different things with arrays and their contents. All of these methods can be found in MDN web docs.
Ref: 07_03
MDN Reference: Array Methods