Harmony mode doesn't seem to enable itself

[hartator]

First of all, thanks for great gem! :)

I seem to not be able to activate the harmony mode of the jsx compiler when using Rails.

I have this in my application.rb:

config.react.jsx_transform_options = {
  harmony: true,
}

One of my component, have a code like this:

 var { checked, ...other } = this.props;

It compiles fine with jsx -x jsx --harmony app/assets/javascripts/components app/assets/javascripts/components:

 var $__0=     this.props,checked=$__0.checked,other=(function(source, exclusion) {var rest = {};var hasOwn = Object.prototype.hasOwnProperty;if (source == null) {throw new TypeError();}for (var key in source) {if (hasOwn.call(source, key) && !hasOwn.call(exclusion, key)) {rest[key] = source[key];}}return rest;})($__0,{checked:1});

But, not inside Rails itself. It stays var { checked, ...other } = this.props; and I got a Uncaught SyntaxError: Unexpected token {. (Other jsx lines compile fine though.)

Any ideas? :/

[hartator]

The harmony spec syntax (https://github.com/reactjs/react-rails/blob/master/test/dummy/app/assets/javascripts/harmony_example.js.jsx#L14) <h1 {...this.props}>{greeting}</h1> "attributes spreading" works actually in my components.

But, the "destructuring assignment" var { checked, ...other } = this.props; is not working.

[rmosolgo]

huh, interesting ... So other transforms work, just not destructuring assignment?

If you're interested in looking into this, you could add a test for destructuring into the tests for this gem.

We get JSXTransformer.js from the react-source gem (loaded here), so if it turns out to be a gem issue, that's the next place I'd look

[hartator]

Okay, will work on that.

Do you know if JSXTransformer.js uses the same code base than jsx command line?

[rmosolgo]

I assume so, but I don't know for sure! Maybe that's part of it.

[hartator]

Humm.. The test I've written is actually working, the compilation is fine. If you want it for the gem test suite: #186

Any idea of something I've missed inside my app? :/

[rmosolgo]

I don't have any good guesses on what's missing. You could double-check the version of your local JSXTransformer.js file. It should be in tmp/react-rails/JSXTransformer.js with a comment at the top saying its version. Can you tell if it's the latest?

[hartator]

I got JSXTransformer v0.12.2.

[hartator]

Okay, I feel like a fool. I've removed the tmp/ directory and restarted everything and now it's working.

For other people that might encounter the same thing, I don't have a definitive explanation, maybe it didn't update correctly the gem or the flag wasn't passed correctly at first.

Thanks Robert! 👍

[rmosolgo]

We're having issues with that way of vendoring in code, it's not just you :S

Thanks for following up!

[hartator]

Good to know! :)

Yeah I feel it's kind of weird to have a react-rails tmp that get copied from elsewhere but there must be good reasons.

[rmosolgo]

I believe it was a page taken out of ember-rails's book:

https://github.com/emberjs/ember-rails/blob/master/lib/ember_rails.rb#L36