This issue was originally filed by email...@daniel-zwicker.de

We have a about 84 dart files in our project with out the libs inside the package folders. There from we have to use dart2js for 15 of them. As a compile to js takes about 10 sec we have tried to speed up this.

We edit the dart2js.dart and changed the 'api.compile(uri....' call to a hard coded URI and double it. So one call to dart2js compile 2 files at once (Yes the out.js will be overwritten).

We mesure the following times (disabled snapshot use of utils_wrapper.dart.snapshot):

file1: 0m8.869s
file2: 0m8.299s

together: 0m12.732s

So there is a speed up of around 50% for the second file. We believe this is because the compiler is loaded.

So wouldn't it be possible to allow to define a directory which dart2js compile all *.dart recursive? This would speed up our builds extreme.