JS Meatballs Pt. 5: Conditionals 🧐

Conditionals

Conditionals are foundational to almost all programming languages. A conditional is a function that is built into JavaScript that we use to create a rule we want the program to follow. The most common conditional is the if() statement.

Let’s take a look:

let numberOfApples = 1;

if (numberOfApples === 1) {
	return 'Eat the apple';
}

> Eat the apple

The statement in the round brackets after the if is called the condition. If the condition evaluates to true, then the code within the curly brackets is run. In this case, the condition is if (1 === 1), because the numberOfApples variable is set to 1. As we know, 1 is equal to 1, so the condition evaluates to true, and the return 'Eat the apple'; is run.

In JavaScript, we have three types of conditionals. These are if(), else if() and else().

let numberOfApples = 9;

if (numberOfApples < 2) {
	return 'Eat the apple';
} else if (numberOfApples <= 6) {
	return 'Bake apple pie';
} else if (numberOfApples <= 8) {
	return 'Bake apple pie';
} else {
	return 'Make apple cider';
}
	
> Make apple cider

In the example above, we can see a block of conditionals. The first conditional is the if statement (which we’ve already seen).

The second is else if which will run return 'Bake apple pie'; if the first if condition is false, and its own condition is true. This if else conditional would be else if (9 <= 6), which evaluates to false, so it won’t run.

Then we can see a second else if() statement. We can have as many else if() statements as we like in a block of conditionals. This else if() evaluates to else if (9 <= 8), which is also false, so the code in its curly brackets isn’t run.

Finally, we have the else. This runs if everything else in the block has failed (which is the case for our example). As such, we see Make apple cider is returned. Cheers!