There is a total of 387k of JS (minified and excluding phonegap.js), but it's important to remember that all of the JS is shipped as part of the native app, so it all lives on device -- none of the JS is shipped over the wire except when the app is downloaded.

We could improve this number, but so far we haven't found that it significantly affects application performance. Mulberry is very conscientious about things that are more likely to affect performance, such as memory leaks as a result of improper component teardown. Apps with incredibly large data sets may experience slowdowns, but there are ways to mitigate that as well. Bottom line: in our year of use of the system, we've been fairly happy with performance, even with 387k of JS>