lit-element + mobx legacy decorators

[tamis-laan]

I'm trying to use lit-element together with mobx, for this i'm using webpack and bable. I'm using the folowing plugins for babel as described in the lit-element docs.

        plugins: [
          ['@babel/plugin-proposal-decorators',{decoratorsBeforeExport: true}],
          ['@babel/plugin-proposal-class-properties'],
        ]

The problem is that mobx requires legacy decorators and crashes when using @computed. However changing the above to:

        plugins: [
          ['@babel/plugin-proposal-decorators', {decoratorsBeforeExport: true, legacy:true}],
          ['@babel/plugin-proposal-class-properties', {legacy:true}],
        ]

Crashes babel with the error:
'decoratorsBeforeExport' can't be used with legacy decorators.

However removing 'decoratorsBeforeExport' breaks lit-element as property changes are no longer registered.

Is there some way to make the two play nice together??

[justinfagnani]

Thanks for the heads up. This is unfortunate. I think the Babel and TypeScript implementations of "legacy" decorators differ slightly. I think we can make it work by checking the arguments to the decorators more carefully.

I don't how this will fall on our priorities for the near term, so we'd definitely take contributions here.

[justinfagnani]

Seems to be a dupe of #205

I'm going to re-open #205 and close this one.