Optimize compile-on-save if for code bases with modules

[mhegazy]

For code bases using modules, it would be safe to emit only modules and their dependencies, but not the whole solution.

Moreover, the --isolatedModules flag ensures that the output is safe to only emit a single file.

[jonaskello]

I'm trying to do hot reloading with tsc -w but it seems impossible since all files are always updated, so the hot-reloader always reloads everything. Any news on this issue? Will it be in 2.0?

[myitcv]

@alexeagle - presumably any Angular 2 app uses modules and so there would be significant benefit to your users if this change were to land?

@mhegazy - this is tagged as 'Visual Studio' but I don't think it's specific to either Visual Studio or "compile-on-save"?

[mhegazy]

This should be done in #9837