[base698]

In my experience Babel minified better than Closure Compiler with less maintenance of the externs on my part.

[cromwellian]

Only possible in simplified mode. I highly doubt Babel comes close with full optimizations turned on in a nontrivial codebase.

[AgentME]

With what plugins? Babel without any plugins or with the common ES2015 plugins doesn't do any minification.

[randomguy7788]

see http://www.syntaxsuccess.com/viewarticle/tree-shaking-in-jav...