Add JSDoc comment to keep license when compiling production code

[andykenward]

When using React in a project along with a module compiler like webpack with UglifyJs to remove comments in code. The current license comment in React is removed as it doesn't conform to JSDoc @license.

I suggest this is added so the license doesnt get removed by default and so people don't have to implement a work around to keep the license in a project.

[gaearon]

Looks good to me, thanks. I’ll leave this open for a few days in case anybody has objections.

[jimfb]

@gaearon Just make sure @zpao and @jamesgpearce see this. It's a pretty minor change, but since it touches the copyright header, it's good to get some eyes (potentially from legal).

@jamesgpearce should we ping legal on this, or is this sufficiently innocuous?

[zpao]

There's nothing legal needs to see here.

I'd prefer not to make this all JSDoc-y. Can we just stick @license above the actual license part (not the copyright) or even just @preserve at the top?

[zpao]

FWIW, this change is only going to impact the react[-*].min.js files that end up on the CDN and in dist/ in the npm package. It's not going to matter for anybody compiling the npm package via browserify or webpack (except for the webpack config that sticks the dist file in and skips the node package)

[andykenward]

@zpao ah you are correct. I will sort that out as that was the point of adding it.

[zpao]

That's going to be much more involved and would require changing every license header we have in src/ (or maybe a new build step). I personally don't think that's worth it and you probably need to make similar changes to other libraries to really be effective. And fwiw, you probably want all of those compiled away with maybe the exception of 1 for file size purposes. Maybe it would be enough to preserve the headers in the entry point (src/isomorphic/React.js).

Can you make sure this works how you expect and describe that case so we have a better idea of what you've tested.

[facebook-github-bot]

@andykenward updated the pull request.

[gaearon]

Let’s remove changes to this one file. Since we already have a header in the React module entry point, this causes license header to be outputted twice in the UMD build.

[zpao]

I actually think I want to keep this so it ends up consistently at the top of all dist files.

But then we would want to add it to the files in packages/react* so that npm-bundled files also have it.

[gaearon]

It wouldn’t be super nice if every react addon added one, would it?

[zpao]

Meh, it'll future proof for when those aren't a part of the react package.

[gaearon]

@zpao Can you clarify which files need to add @license? e.g. does ReactDOM entry point need one? LinkedInput? Every addon?