What are the differences between Type Guards and Type Assertions in TypeScript?

What are the differences between Type Guards and Type Assertions in TypeScript?

Type Guards are functions that check the type of a variable at runtime, while Type Assertions tell the compiler to treat a variable as a specific type without checking.

Can you give me an example of a Type Guard?

Sure! Here's a simple example:

function isString(value: any): value is string {
    return typeof value === 'string';
}

This function checks if the value is a string.

And how would I use Type Assertions?

You can use Type Assertions like this:

let someValue: any = "this is a string";
let strLength: number = (someValue as string).length;

Here, we assert that someValue is a string.

When should I use Type Guards instead of Type Assertions?

Use Type Guards when you need runtime type checking, especially in complex applications. Type Assertions should be used when you're confident about the type and want to bypass the compiler's checks.