Build umd with rollup

[TrySound]

Ref #2245

[TrySound]

40 461 b -> 27 793 b
10 738 b -> 7 503 b

[gaearon]

CI seems to fail because of ES3ify check.
But while we're at it, why does the compiled bundle have .default anywhere at all?

[TrySound]

Nice catch. symbol-observable has only jsnext:main which is disabled by default.

[timdorr]

@gaearon

But while we're at it, why does the compiled bundle have .default anywhere at all?

That is the way Babel 6 handles export default. @kentcdodds wrote about it, but here's why:

// foo.js
const foo = {baz: 42, bar: false}
export default foo
// bar.js
import {baz} from './foo' // <-- Not allowed!

That is against the spec (though it may have changed since 6.0.0), so they "broke" that behavior to fix the spec. Hence, all defaults are exported in the default property of the module.

[gaearon]

Right, but if we're bundling with rollup, we need to let it handle ES modules instead of Babel. So we should change the rollup env to not do the commonjs transform.

[gaearon]

@TrySound Can you post resulting bundles as gists for comparison?

[timdorr]

BTW, we're down to:

26843 dist/redux.js
 7159 dist/redux.min.js

👍

Here's the latest build artifacts for easy perusal: https://gist.github.com/timdorr/73a8d368c1d0c3d3c83aa73af8f02cbe

As compared to before: https://unpkg.com/redux@3.6.0/dist/redux.js

[timdorr]

LGTM. Most of the cost savings are from the babel import/export transforms and the inter-module imports (__webpack_require__ stuff). Surprisingly hefty! Here's hoping webpack 2 can add scope hoisting soon...

[gaearon]

This part worries me a little. Does it inline in prod build?

[TrySound]

Yeah. This increases bundle. Weird behavior.

[gaearon]

Could be #2244, I'm not sure if it was fixed yet in master.

[timdorr]

Now:

26843 dist/redux.js
 7023 dist/redux.min.js

Keep going!

[TrySound]

@gaearon Yeah. Current min release is smaller because of that thing. Inference with code elimination is too hard :) That PR should be reverted.

[timdorr]

I'll merge it in here and then merge in this PR. The reason for #2030 are something you can fix with tooling.

[TrySound]

Do you guys want to release it as 3.* or 4.*?

[timdorr]

@TrySound Can you enable contributor pushing to your branch? Should be a checkbox at the top of the PR.

[timdorr]

Once I can push it, reverting that takes us down to:

26636 dist/redux.js
 5827 dist/redux.min.js

Now we're cooking.

[TrySound]

Yay!

@timdorr It's enabled.

[timdorr]

Cool, I think we're good. This doesn't change anything outside of the UMD build and does so in entirely a compatible way, so I think it only needs a patch version. Correct me if I'm wrong, otherwise I'll push this as 3.6.1. I don't believe we've had any other non-docs/examples updates since that release.

[gaearon]

It's probably safe as a patch. Maybe as a minor for a tiny bit of extra safety.

[TrySound]

Okay. I just would like to remove jsnext:main which is legacy. Rollup uses module field now. But guys still add this field looking at this and similar packages. But it will be breaking change.

[timdorr]

Go ahead and do that against the next branch, which is our target for 4.0 stuff.

AFAIK, webpack is following suit, so that should be a low-impact breaking change for most folks.

[timdorr]

BTW, thanks for the hustle on this!