use uglifyjs-webpack-plugin v1

[viankakrisna]

as quoted by the readme https://github.com/webpack-contrib/uglifyjs-webpack-plugin:

webpack =< v3.0.0 currently contains v0.4.6 of this plugin under webpack.optimize.UglifyJsPlugin as an alias. For usage of the latest version (v1.0.0), please follow the instructions below. Aliasing v1.0.0 as webpack.optimize.UglifyJsPlugin is scheduled for webpack v4.0.0

The v1 is released on October, so I think it's mature enough to switch to v1 in CRA? or do we want to wait for webpack 4?

Pro:

This allows us to use uglify-es and access to parallel and cache options. Hence improving our build speed.

Con:

I haven't test it yet, but maybe this will break our parsing of uglify error #2650

[Timer]

Oops, accidentally merged this to master. You can find this in next now.

[sohkai]

Is there any chance of this getting into a 1.1.2 (or similar) release? This will fix a lot of the minifying problems.

[Timer]

No, this will not be released in a 1.1.2 release. Sorry!

This is not a minifying problem, but as that link explains it's a problem with the libraries you're importing.
Due the the sheer amount of improperly published packages in the ecosystem, v2 addresses this. Please engage in the betas and provide feedback!