Add back React.__spread and make it warn

[zpao]

This API was removed because it was undocumented and existed solely for our JSXTransformer/react-tools, which haven't been supported for a year. However it turns out TypeScript is still using this API in their TSX compilation and it kind of sucks to break people who want to upgrade React but not the rest of their toolchain.

Note: this doesn't quite (read at all) work with the Object.assign -> object-assign transform I wrote so would need to fix that too.

[sebmarkbage]

Can we make it say something about TypeScript and JSTransformer specifically so people know how to upgrade?

[sophiebits]

nit: add trailing period

[KyleAMathews]

Coffee-React uses it as well fwiw https://github.com/jsdf/coffee-react#spread-attributes

[zpao]

Going to make this Object.assign.apply(null, arguments) (shouldn't matter but makes more sense when compiling to use object-assign. `_assign.apply(null, arguments)

[gaearon]

At least these days we know how to name things.

[kuon]

Maybe state in the comment that this is deprecated and evil to use?

[sebmarkbage]

I originally confused this with https://github.com/facebook/react-native/blob/master/Libraries/ReactNative/ReactNative.js#L96 and got overexcited to kill this too. I should've deprecated it first.

[zpao]

Can we make it say something about TypeScript and JSTransformer specifically so people know how to upgrade?

Better? I figured we could just link to a page on the wiki that discusses typescriupt and coffeescript specifically instead of putting it in the warning.

[sebmarkbage]

👍

[facebook-github-bot]

@zpao updated the pull request.

[zpao]

Just going to point that fb.me url here for the time being. We can change it later, but I'm optimizing for the path which gets me to a drink fastest.

[facebook-github-bot]

@zpao updated the pull request.

[glenjamin]

Seeing a few people pop up in support channels with this issue - might be worth adding a note to the v15 announcement?

Medium-term: I wonder if there's a good way to automatically check compatibility with widely used downstream projects against RCs. I know really that should be downstream's responsibility - but I wonder if there's anything React's team/community can do to help.

[m4tthumphrey]

This bit me on the bum when I just upgraded to 15.0. I get that it's been deprecated/removed but even after reading this thread I'm a confused on what I need to do fix it?

Edit: I think I need to point out that I'm not using React.__spread myself; my render method looks like

return (
  <input type="text" value={value} onChange={onChange} className={classeNames} {...other} />
);

and the ...other transpiled to

React.spread(..)

Does this make a difference?

[gaearon]

@m4tthumphrey

This is not a problem with your code. It's a problem with whatever tool you use to compile JSX.

If you are using react-tools to compile JSX, please switch to Babel. That project was unsupported for more than a year.

The fix will be out today because TypeScript still depends on it but this method is still deprecated so please try to migrate to tools that don't use it.

[m4tthumphrey]

@gaearon Thanks Dan, thats what I thought. Forgive me but how do I switch from using react-tools to babel? I already tried this morning after reading through the blog post but didn't really know what I was doing..?

[gaearon]

How do you compile JSX?

[m4tthumphrey]

@gaearon

webpack loaders..

module.exports = {
  entry: './js/app.js',
  output: {
    filename: './bundle.js',
    path: './static/'
  },
  module: {
    loaders: [
      {
        test: /\.js$/,
        loader: 'jsx?harmony'
      },
      {
        test: /\.(png|jpg|gif)$/,
        loader: 'url?limit=8192'
      },
      {
        test: /\.css$/,
        loader: 'style!css'
      }
    ]
  }
};

[gaearon]

You are using jsx-loader which uses deprecated react-tools. Replace it with babel-loader. Then configure Babel to use es2015 and react presets and you should be good.

[m4tthumphrey]

Ahh I see, great than you Dan.

On 8 April 2016 at 16:01, Dan Abramov [email protected] wrote:

You are using jsx-loader which uses deprecated react-tools. Replace it
with babel-loader. Then configure Babel to use es2015 and react presets
and you should be good.

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#6444 (comment)

[dsifford]

@gaearon

You are using jsx-loader which uses deprecated react-tools. Replace it with babel-loader. Then configure Babel to use es2015 and react presets and you should be good.

I'm doing these things now and still getting the depreciation warning. Is this to be expected until Typescript fixes whatever internals they need to fix? Or should I investigate further?

[gaearon]

I'm doing these things now and still getting the depreciation warning. Is this to be expected until Typescript fixes whatever internals they need to fix?

If you use TypeScript, yes, you will need for them to release the fix.

[dsifford]

Ok great that's what I assumed. Thanks for the clarification 👍

[DanielRosenwasser]

As a heads up, this should now be fixed in TypeScript 1.8.10.

[zpao]

Thanks @DanielRosenwasser, I appreciate the quick turn around! Sorry for the surprise breakage.

[DanielRosenwasser]

No worries - I've been trying to keep a better eye on the activity of the repo since this all first went down. We really appreciate how quick the React team was to get a fix out!