[robust-cactus]

The history here is a little misleading. Client side bundling happened before node/npm. It's a performance optimization to reduce the number of requests the browser has to make. Typically people were just concatenating files. Concatenating was a painful dependency management challenge for larger code bases. Subsequently there were module systems like requirejs that also sought to fix some problems like these and ran without a build step in dev. Browserify really changed the perspective here and people started to think a build step wasn't sooo bad.

I do think, based on the requirejs code that commonjs/browserify didn't really need to be compiled anyways.

Also fwiw, the technique mentioned here is a way a colleague and myself introduced babel to a large company as well, we just transformed + reverse proxy cached in dev. And fwiw, webpack basically does this anyways these days.