Can you explain what the keyword Typealias is in the Swift programming language?

In Swift, the keyword typealias is used to create a new name (alias) for an existing type. This helps make the code more readable and convenient, especially when working with complex types.

For example, if you have a long type, such as a function with multiple parameters, you can create an alias for it:

// Define an alias for a function type
typealias CompletionHandler = (Bool, Error?) -> Void

func fetchData(completion: CompletionHandler) {
    // implementation
}

Also, typealias is useful for simplifying type names, for example, when working with tuples or generics.