Add loose-envify transform to package.json

[chrisvasz]

We are building our application using Browserify. When including react-virtualized through Browserify, the process.env.NODE_ENV checks are not processed, causing Browserify to include a process shim in the bundle. This bloats the bundle size and reduces opportunity for minification since "development" !== "production" checks are no longer removable.

This PR tells Browserify to apply the loose-envify transform when react-virtualized is included in a Browserify bundle. After applying this change, process.env.NODE_ENV is correctly replaced during our build process.

Other libraries, such as Redux, use this method to provide process.env replacement too -- see here for the relevant commit on Redux.

[bvaughn]

Hi @chrisvasz,

Thanks for the PR. 😄

I don't think loose-envify should not be added as a dependency for react-virtualized since (a) it isn't a runtime dependency and (b) not everyone uses Browserify. I think this package.json entry is just for projects that use Browserify to bundle JS, no?

Disclaimer: I'm not very familiar with Browserify.

[bvaughn]

I'm going to commit the new browserify block by itself. If anything, it seems like loose-envify should be a devDependencies in an external project that actually uses Browserify. (react-virtualized uses Babel+Webpack so it doesn't seem appropriate to add the devDependencies here.) Please let me know if I've misunderstood anything. 😄

[chrisvasz]

Thanks! This will save us about 7kb in production because of the propTypes removal and because Browserify will no longer include a process shim. Woohoo!

I do think loose-envify needs to be a dependency though. In my case, without the dependencies entry, this happens to work because I use other modules that require loose-envify and Browserify can find it in node_modules. If I remove the other projects that depend on loose-envify, my build breaks because Browserify can't find the loose-envify module.

From what I can tell, this is actually the reason Redux specifies loose-envify as a dependency (not a devDependency) also. Check out this conversation and this followup PR.

[bvaughn]

Good call @chrisvasz. If you'd be willing to make a PR similar to reduxjs/redux/pull/1306 I'll accept it. Thanks again!

[chrisvasz]

All over it. Thanks!

[bvaughn]

Circling back to this because I found myself, again, wondering why we had to list loose-envify as a dependency instead of a dev dependency.