Add reasonable uglify-js options.

[rwjblue]

These options should always have been specified, and are good defaults.

I could have sworn that these defaults were already present, but I could not find them in this repo, in ember-cli-uglify repo, or the broccoli-uglify-sourcemap repo...

[krisselden]

@rwjblue should we not deep merge?

[rwjblue]

@krisselden - We do merge deeply via lodash.defaultsDeep here.

[stefanpenner]

@rwjblue [BUGFIX release] ?

[rwjblue]

This targets beta at the moment. I'm fine with release also, can update the PR target in the morning.

[stefanpenner]

This targets beta at the moment. I'm fine with release also, can update the PR target in the morning.

seems likely good to get this out asap IMHO.

[rwjblue]

retargeted and rebased

[stefanpenner]

[cibernox]

Out of curiosity, how does this affect performance?

[stefanpenner]

@cibernox what performance are you curious about build/runtime?

[cibernox]

Precisely. This is tagged as performance but it's not clear to me to which one it refers. I assume it refers to some sort IIFE optimization, and I'm curious to read more about that.

[stefanpenner]

@cibernox TL;DR

uglify stripped the leading ( here define('asdf',[], (function() { } )), preventing https://www.npmjs.com/package/ember-cli-optimize from working. more details here

[krisselden]

@cibernox negate_iife hurts the performance at runtime of parsing IIFE to save one character. Turning statements into sequences, like a series of define() statements is also costly at parsing, but @rwjblue would have needed to set it to sequences: false or 0