A callback interface

[ericclemmons]

A callback interface

[ericclemmons]

Do you mean a Promise-free version (top to bottom), or you'd like the ability to do node-style callback resolution in the resolve block?

The internals are doing a Promise.all, so there would need to be some core equivalency here, whether with an outside dependency (async?) or similar...

[goatslacker]

Top to bottom would be nice but that's just a pipe dream. Just the ability to do callbacks or whatever in the resolve block is a good start.

Yeah you would need async.parallel

[ericclemmons]

I can pretty easily add back in callback support in the resolve block based on the arity (is that the right word?) of the function.

Behind the scenes, it'll use a Promise to map it.

Is that ok for now?

I didn't know if Promises should be avoided in your estimation, or what?

[goatslacker]

No it's not necessary to avoid them. As long as resolver isn't swallowing errors promises are great.

[ericclemmons]

I... guess we're fine then? I do know it's recommended to do Resolver.renderSomehow(...).catch(...), since it's promise-driven.

[srph]

I like the idea as well. I'm starting to like generators recently.

[goatslacker]

Pseudo-code:

// where you resolve the promises:
return new Promise((resolve, reject) => {
  // create a node-style callback
  const callback = (err, value) => err ? reject(err) : resolve(value);

  // call the resolve prop
  const value = resolveProp(props, context, callback);

  // if a Promise is returned then attach to it.
  if (value && value.then && typeof value.then === 'function') {
    value.then(resolve).catch(reject)
  }
})

[ericclemmons]

Ahhhh, that takes me back :)

react-resolver/src/mixin.js

Lines 48 to 54 in b7a46a1

	if (value.length) {
	return new Bluebird(function(resolve, reject) {
	value.call(this, function(err, result) {
	err ? reject(err) : resolve(result);
	});
	}.bind(this));
	}

That was a simpler time!

Nice code, BTW. That solves it pretty well.

Now I'm curious. I guess I still use promises wrong??

https://github.com/petkaantonov/bluebird/wiki/Promise-anti-patterns#the-thensuccess-fail-anti-pattern

[goatslacker]

I think if you return the promise itself you'll be a-ok since it'll unwrap itself. I'm probably doing it wrong.

[ericclemmons]

Oh no, I think you're right. In one of the other issues, I opted for .then(resolved, rejected), whereas I should've just used .then(resolved).catch(errored).

[ericclemmons]

v2 is a complete-rewrap & will support decorators & a better mechanism with dealing with errors.

TBH, callbacks are soooo great for error states :) Closing to start fresh post-v2...