Arrays also work closely together with another common feature in

JavaScript, loops.

Loops are a powerful tool in programming.

A loop is a way to repeat the same actions a certain number of times.

Now, there are many different types of loops available to use in JavaScript.

But they all essentially do the same thing,

they repeat an action a given number of times.

So here I'll cover two common ways you might see loops written in modern

JavaScript.

First is the for-each loop.

For-each is simply a loop that accesses each item in an array.

So for example, instead of manually accessing each element in an array by

index like I showed you earlier, we can use a loop to do it for us.

So we could, for instance, write a loop that grabs each movie title in the movies

array, and converts them into an HTML list with links the user can click.

To write a for-each loop, you first put the variable name of the array,

then .forEach and a set of parentheses.

Inside the parentheses, you provide for-each a function to run and

complete once for each item inside the array.

You'll hear this type of function referred to as a callback function.

For this example, I'll write a function that pops up an alert box for

each movie title in the movies array.

The function will take one parameter, I'll call it movie.

The parameter movie represents the current element or

movie title being processed here in the array.

And notice that there's no name after the function keyword this time,

because it has no name.

It's called an anonymous function.

You'll often use anonymous functions to pass functions as parameters

to another function.

So inside the body of the function, or between the curly braces,

we can do whatever we want with each item in the array.

So I'm gonna pop up an alert dialogue box for each movie title in the array.

I'll type alert, and pass it movie.

So forEach is going to call the function passed to it,

for each element in the movies array.

When the function is called, a movie title is passed into the movie argument,

then the next, the next, and so on.

The loop stops when it has reached the end of the movies array, and

there are no more movie titles to pop up in the alert box.

So this is just a simple example of how loops in JavaScript

manage the process of accessing each element in an array for you.

Many programmers find for-each easier to read

than some of the other ways of writing loops.

The code in a for-each loop is easier to and

understand, and usually involves less codes.