How do I use type annotations in TypeScript?

How do I use type annotations in TypeScript?

Type annotations in TypeScript allow you to specify the types of variables, function parameters, and return values. For example, you can declare a variable with a specific type like this: let age: number = 30;.

Can you give me an example of a function with type annotations?

Sure! Here's a simple function that takes a string and a number as parameters and returns a string:

function greet(name: string, age: number): string {
    return `Hello, my name is ${name} and I am ${age} years old.`;
}

What happens if I don't use type annotations?

If you don't use type annotations, TypeScript will infer the types based on the assigned values. However, this can lead to less clarity and potential runtime errors if the inferred types are not what you expect.

Are there any best practices for using type annotations?

Yes! Some best practices include using type annotations for function parameters and return types, avoiding the use of the any type, and leveraging interfaces and types for complex structures.