What is the difference between type assertions and type casting in TypeScript?

What is the difference between type assertions and type casting in TypeScript?

Type assertions and type casting are often confused, but they serve different purposes. Type assertions tell the compiler to treat a variable as a specific type without changing its actual type, while type casting converts a variable from one type to another.

Can you give me an example of type assertions?

Sure! In TypeScript, you can use the 'as' keyword for type assertions. For example: let someValue: any = 'this is a string'; let strLength: number = (someValue as string).length; This tells TypeScript to treat someValue as a string.

And what about type casting?

Type casting is more about converting types. For instance, if you have a variable of type 'any', you can cast it to a specific type like this: let someValue: any = 'this is a string'; let strLength: number = (<string>someValue).length; This changes how TypeScript interprets the variable.

Are there any performance differences between the two?

No, there are no performance differences between type assertions and type casting in TypeScript. Both are compile-time constructs and do not affect the runtime performance.