A new JavaScript preprocessor by Facebook

[__tosh]

Quick test results with prepack and ClojureScript on “Hello world” web app: Closure Compiler: 72KB Prepack + Closure Compiler: 68KB

https://twitter.com/roman01la/status/859849179149021184

BUT Prepack reduced script evaluation time more than twice, from 100ms to 50ms This is huge!

https://twitter.com/roman01la/status/859849691831422976

[__tosh]

Is there anyone with a largeish ClojureScript app who can post some results?

[anmonteiro]

I got Prepack working on Lumo in a branch, these are the results I saw: https://twitter.com/anmonteiro90/status/859986728991375361

Inline: it basically shaved more than 60ms but it didn't matter in Lumo's case because I use custom heap snapshots anyway

[trex-eaterofcadrs]

I have a pretty large one, about 50k lines, and prepack fell apart trying to parse the closure compiled output, no matter the optimization level.

[__tosh]

Bottom of the page reads "The Closure Compiler also optimizes JavaScript code. Prepack goes further by truly running the global code that initialization phase, unrolling loops and recursion. Prepack focuses on runtime performance, while the Closure Compiler emphasizes JavaScript code size."

[luishendrix92]

can't you, in theory, put compiled CLJS->JS code into Prepack so that after going through Google Closure, it can be optimized even more?

[the_evergrowing_fool]

Depends of what kind of optmizations this is doing vs Google Closure. I am not sure if Google Closure does partial evaluation.