What are the differences between type assertions and type guards in TypeScript?

What are the differences between type assertions and type guards in TypeScript?

Type assertions are a way to tell the TypeScript compiler to treat a variable as a specific type, while type guards are functions or expressions that check the type of a variable at runtime.

Can you give me an example of type assertions?

Sure! For instance, if you have a variable let value: any = 'Hello';, you can assert its type like this: let str: string = value as string;.

And what about type guards?

Type guards can be implemented using the typeof operator. For example: if (typeof value === 'string') { // value is a string }.

When should I use type assertions over type guards?

Use type assertions when you're confident about the type and want to bypass TypeScript's checks. Use type guards when you need to ensure the type at runtime.