[xsmasher]

This is "stunt programming," similar to shooting an arrow into a target from horseback in a rodeo. It has little to do with the real-life business of real-life cowboys.

In this case it's using the type system to calculate the answer to a problem, which is not useful because the type system can't output anything to the console or do other IO. The "answer" will only be visible in your IDE.

The type system is powerful and extremely capable because it had to support existing javascript patterns, like "this function takes a parameter that might be a string or might be a number or might be an array" and make them type-safe.