This isn't ideal since it doesn't do any compressing. Richard suggested using:
$ webpack --optimize-minimize --optimize-dedupe
But when I run it here it throws some errors I have to dig into...
$ npm run clientize
> page-metadata-parser@0.4.1 clientize /Users/pdehaan/dev/github/mozilla/page-metadata-parser
> webpack
[BABEL] Note: The code generator has deoptimised the styling of "/Users/pdehaan/dev/github/mozilla/page-metadata-parser/node_modules/wu/dist/wu.js" as it exceeds the max of "100KB".
Hash: fb2fc43f052c74004a87
Version: webpack 1.13.2
Time: 7381ms
Asset Size Chunks Chunk Names
page-metadata-parser.bundle.js 490 kB 0 [emitted] main
[0] multi main 40 bytes {0} [built]
+ 308 hidden modules
Ref https://github.com/mozilla/page-metadata-parser/pull/68#pullrequestreview-577203