Prototypical Record Types?

[JAForbes]

Currently $.RecordType checks a value via Object.keys. Object.keys will not pick up prototypical properties and methods.

I think it'd be pretty helpful to be able to define types that include prototypes.

E.g.

const $Promise = 
  $.RecordType({
    then: $.AnyFunction
    ,catch: $.AnyFunction
  })

Maybe $Promise isn't the best example, we'd probably want to use a BinaryType in that case. But even internally we could use the above in the validator for a BinaryType version for brevity.

[davidchambers]

I agree. The Sanctuary way seems to be to respect enumerable keys, regardless of where they're defined. Would you like to submit a pull request for this change, James?

[JAForbes]

Yeah sure 😄

[davidchambers]

#164:

It would be a shame not to support prototypal inheritance, as I consider it one of the good parts of JavaScript. I suggest we state that a field is an enumerable property. Note that this means that Promise.resolve(42) is not a member of $.RecordType({then: $.AnyFunction}) as @JAForbes requested in #141. I can live with this. One could define an equivalent type via $.NullaryType (or even $.UnaryType).