How to match both on type (instance of) and property values

[snowfrogdev]

Hey, I was thinking of implementing pattern matching myself when I stumbled upon your wonderful project. Very cool. And I'm hoping it'll save me from having to roll out my own thing, if I even have enough drive to do it 😁. Now...

Given this:

abstract class Option<T> {
  constructor(protected value: T) { }
  
  // bunch of methods
}

class Some<T> extends Option <T> {
  constructor(value: T) { super(value) }
}

class None extends Option <void> {
  constructor(value: T) { super(value) }
}

Using ts-pattern, how do I do something functionally equivalent to this:

const something = new Some(Math.random());
const nothing = new None();

const somethingOrNothing = () =>  Math.random() > 0.5 ? something : nothing;

match(somethingOrNothing())
  .with(new Some(select('value'), (value) => `OMG it matched and the value is ${value}`)
  .with(new None(), () => 'Nothing to see here') 
  .exhaustive()

// or

match(somethingOrNothing())
  .with(new Some(__), () => `OMG it matched and I don't care about the value`)
  .with(new None(), () => 'Nothing to see here') 
  .exhaustive()  

// or 

match(somethingOrNothing())
  .with(new Some(0.7)), () => `OMG I can't believe I guessed the number`)
  .with(new Some(__), => `The value is something else than 0.7`)
  .with(new None(), () => 'Nothing to see here') 
  .exhaustive()  

I think you get what I'm trying to do. The same kind of pattern matching that you would do on Result and Option types in rust. I've used a class hierarchy here but if it helps in any way, I could do this instead:

interface Option<T> {
  // bunch of methods
}

class Some<T> implements Option<T> {
  constructor(private value: T) {}
 // bunch of methods
}

class None implements Option<void> {
  // bunch of methods
}