While contemplating how to further complicate the if statement, specifically the condition block, thanks to the benevolent developers of TypeScript and JavaScript, you can now use multiple conditions in a single block.

For example, you need to set two conditions: the number must be greater than 0 AND less than 99. (For instance, you're a seller of LEGO sets)

As you can see, we've set a double condition. We need the age to be greater than 0 AND less than 99. To achieve this, we used symbols like &&. There's another option, which is when we need to set multiple conditions, and any of them can be satisfied. In simpler terms - OR. Let's take a look at an example:

As you can see, we used || to set the OR condition. In our code above, if the grade is Very well or Good, then we've done our job well. Let's quickly remember these keywords:

1. AND = &&;
2. OR = ||.

• true && false = false;
• true && true = true;
• false && false = false;
• true || true = true;
• true || false = true;
• false || false = false.

By the way, you can use multiple such conditions simultaneously. For example, you may need 3 or 4 of them. For instance, if we need to retrieve a number between 20 and 50 OR between 70 and 100:

We can group conditions in parentheses, just like in mathematics. This means that conditions within the parentheses will be checked first, and then conditions outside the parentheses will be evaluated.