Anthony G

Agreed that `Eq.struct({})` should not be allowed, and is unexpected behavior - all keys should be required However, under this implementation ```ts const keyExists = { a: 123, b: undefined...

There would theoretically also have to be a couple versions of `withUndefined`, an inclusive one where `undefined === undefined`, and an exclusive one where `undefined !== undefined`, since it can...

Another idea is that we could take inspiration from monocle-ts `atKey`, and use an `Option` type - the outer `Option` is `none` if the key is missing, and the inner...

I think a lot of fp-ts users would agree w/ you that js's treatment and use of `undefined` is frustrating - that's why we've avoided it in favor of `Option`,...

You've got a good instinct, it turns out what I wrote is impossible to achieve at runtime, since you can't know whether a key is partial or not at the...

That's great, I'm glad you like them! Ok it sounds like we have Just a note: this [already exists for Eq](https://github.com/gcanti/io-ts/blob/master/Eq.md), inside the module `io-ts`. Maybe 'semigroup' and 'monoid' also...

[retryWhen](https://www.learnrxjs.io/learn-rxjs/operators/error_handling/retrywhen) would also be cool

They should be pipeable, I think the tricky thing is that they aren't transformed with Either, so the types don't quite match up: ```ts const b = pipe( from([1, 2,...

Here's a simple example usage ```ts import {pipe} from 'fp-ts/pipeable' import * as r from 'rxjs' import * as E from 'fp-ts/Either' import * as OB from 'fp-ts-rxjs/lib/Observable' import *...

Just a note - this solution is not ideal, because the input observable is subscribed to twice due to the `r.merge` call. The redundant emissions are filtered out, but it...