Addon Error "Cannot read property 'emit' of null"

[thani-sh]

Related issue: https://github.com/mthuret/storybook-addon-specifications/issues/1

This issue is somewhat weird:

@tomitrescak got the error message

Cannot read property 'emit' of null

Which means that the addons variable here must be already available and addons.getChannel() call was successful. Which means @kadira/storybook-addons was already available.

The weird thing is that it started working once he installed @kadira/storybook-addons. Maybe it was some node module version mixups or its something else.

I checked the mthuret/storybook-addon-specifications code and the way it's using addons.getChannel() is fine. I tried setting up this addon with the react-button repo and it also worked fine.

cc: @arunoda @roonyh

[arunoda]

We need to check with @tomitrescak he is using NPM2?

[arunoda]

We need to do some webpack hack and try to load the same @kadira/storybook-addons in all the cases. (Using webpack's alias)

Then we may use @kadira/storybook-addons as a peer dependancy. Not sure this'll fix that issue, then we know everyone on the same page.

[thani-sh]

All addons have @kadira/storybook-addons as a peer dependency and @kadira/storybook has it as a dependency. So it should work fine, right?

[arunoda]

@mnmtanish Ah yes. In that case, it should work properly. May be the version of @kadira/storybook-addons in the @kadira/storybook is a older one. Which don't have that emit method.

So, when the user installed @kadira/storybook-addons manually it will show up properly.

[thani-sh]

The emit method comes from the channel. From the error we can see that the user got null instead of the channel. This can happen when multiple versions of @kadira/storybook-addons gets loaded somehow. I think the one on react-storybook gets the addons.setChannel call and the one (somehow) loaded by the addon gets the addons.getChannel call.

Is there any node feature to make sure only one version of a module gets loaded? Is it okay to use a global variable to check whether multiple versions are loaded?

[tomitrescak]

Guys, the error was that I was using older version of storybook ... shame on me :/

[arunoda]

Thanks @tomitrescak. The think I guess might be correct. I think we can close this now.

[darthtrevino]

FYI, if you run into this while developing addons, I had to update .storybook/webpack.config.js:

const path = require('path');
module.exports = {
  ...<your wepback conf>...
  resolve: {
    alias: {
      '@kadira/storybook-addons': path.join(__dirname, '../node_modules/@kadira/storybook-addons'),
    },
  },
};