[RFC] Always expand objects if contained in another object or array

[vjeux]

The flow tests look really bad with it but the more real world tests feel much better. I think we'll have to run that on a real codebase and see how it feels.

Fixes #74

[jlongster]

I wonder if we added one more condition to the heuristic: there are 2 or more properties in the object. I realized that we would break cases like { foo: { bar: { baz: 5 } } } which look nice collapsed, but once you get more than one it makes sense to expand them. What do you think?

[yamafaktory]

@vjeux this doesn't have any effect with the Flow parser, e.g.:

const a = {b: 5,c: 4,d: {e,f: {}}};

outputs (Babylon):

const a = {
  b: 5,
  c: 4,
  d: {
    e,
    f: {}
  }
};

with Flow:

const a = { b: 5, c: 4, d: { e, f: {} } };

[vjeux]

After thinking more about it, I think that the key property we want is consistency between all the objects of an object/array. So, if there's one object in an object that would be split, then we need to split all of them.

I don't think that the current IR supports this kind of behavior but I think that it would solve a lot of the problems with objects expansion.

[jlongster]

Yeah, that's too complicated for the printer. That would require something like browser's "reflow" capability where it sees something doesn't fit and can arbitrarily reflow any part of the output. It's not only complicated but could worsen performance.

It's going to be easier to have a heuristic that we can apply statically at IR-generation time.

[vjeux]

We need to think more about this problem. I don't think that this idea is going to work out well.