UglifyJS

My understanding is that Uglify is just a JS to JS transform, and there isn't a way for Reason to supply type information. At least, I don't see anything about it in the README: https://github.com/mishoo/UglifyJS Also note that, at least with Flow and TypeScript, type information isn't guaranteed to be correct, so it's a bit dangerous to do type-based optimizations (although tools certainly could try, with the caveat that if your types are wrong, your code may break even more than it otherwise would).

There is a separate branch for ES2015+ here: https://github.com/mishoo/UglifyJS2/tree/harmony The new primary committer, alexlamsl, is good about responding to bugs & pushing out new versions fast: https://github.com/mishoo/UglifyJS2/issues?q=is%3Aissue+is%3... But there is still no CHANGELOG. He is aggressive at updating the docs, so you'll have to look at diffs yourself.

Support for pure annotations was added. https://github.com/mishoo/UglifyJS2/commit/1e51586996ae4fdac... This will enable removing unused transpiled classes from e.g. Babel. See https://github.com/mishoo/UglifyJS2/issues/1261

Given the (rude and unhelpful) reply from the team, I suppose it was a premature release. https://github.com/mishoo/UglifyJS2/issues/1875

UglifyJS2 also supports this with the --mangle-props option [1]. Is there something different about how this is done in UglifyJS3? [1] https://github.com/mishoo/UglifyJS2/blob/master/README.md#us...

Here are the commits. Looks like the biggest backwards compatibility issue comes from the "Drop Angular" commit. He also changed the screw_ie8 option to be called ie8 now. A few bug fixes, too, but I'm definitely paraphrasing here. https://github.com/mishoo/UglifyJS2/compare/v2.8.23...v3.0.0

Uglify has had many years to at least attempt to minify ES2015+. They just haven't—it's still an "experimental" branch in their repo: https://github.com/mishoo/UglifyJS2/issues/448 I agree with your comment, but at some point, devs will get impatient.

Feb 4th. https://github.com/mishoo/UglifyJS2/issues/936#issuecomment-...

Ironically the same person who first reported this npm vulnerability used the wrong package name uglifyjs instead of uglify-js in an unrelated github project. https://github.com/mishoo/UglifyJS2/issues/936#issuecomment-... https://github.com/samccone/The-cost-of-transpiling-es2015-i... Or perhaps was it a security experiment to see how long it took someone to notice.

Just to share, there is an issue about uglifyjs https://github.com/mishoo/UglifyJS2/issues/936

-j4 says use up to 4 processes in parallel. Make has a jobserver that does parallelism safely with respect to the dependency graph. So for example, even if we have workers to spare, it won't try to build all.min.js until all of the .ugly files have finished building. The %.foo : %.bar things are pattern rules. [1] The $<, $@, and $^ things are called automatic variables. [2] They correspond to the first input file for a rule, the target file for a rule, and the complete list of input files for a rule, respectively. Cryptic at first but really handy. There's a standalone script for UglifyJS. [3] [1] https://www.gnu.org/software/make/manual/html_node/Pattern-M... [2] https://www.gnu.org/software/make/manual/html_node/Automatic... [3] https://github.com/mishoo/UglifyJS2/blob/master/bin/uglifyjs

Yeah, it gives me 29 errors. You might as well use UglifyJS, the same compressor that jQuery uses. https://github.com/mishoo/UglifyJS2/ You can try it out on http://skalman.github.io/UglifyJS-online/. It's just a light-weight wrapper.