Consider adding type coercion

[notatestuser]

It'd be nice to be able to coerce convertible types to other types.

const PersonRecord = Record({
  id: String,
  phone: Coerce(Union(Number, String), String),
}, 'Person');

In this hypothetical example if we did the following:

const p1 = PersonRecord({ id: 0, phone: 12318001800 });

accessing p1.phone would give us a string.

We'd have to keep a map of how we get from one type to others. This could be hard-coded or supplied at run-time.

[stutrek]

I like it because it's explicit

[notatestuser]

I could have a stab at implementing this if you think it would be a worthwhile feature.

[stutrek]

I think people will like it. I think @udnisap implemented something similar but didn't put it in a PR.