Sometimes you might know a more specific type than TypeScript can infer. In these cases, you can use type assertions to specify the type you're confident about.
let someValue: any = "This is a string";
let strLength: number = (<string>someValue).length;
// Or using as-syntax
let strLengthAs: number = (someValue as string).length;
In general, type assertions should be avoided if possible. But sometimes it is impossible, especially when dealing with JSON serialization and deserialization from a server, for example.
You are given a variable of type
any that is supposed to contain a string. Write a function that takes this variable and returns the length of the string using type assertions.