`noEmitOnError` slows down incremental per file emit

[basarat]

This might be by design. I'm creating this issue purely for clarity 🌹

Basically services.getEmitOutput(filePath); goes from under 10ms to over 1.5seconds probably because it seems to validate the whole project. So we can't do a file by file emit.

First reported by @robertknight here : TypeStrong/atom-typescript#590

[mhegazy]

yup. that is by design. when you have noEmitOnError, you are asking the compiler not to emit any files if there is any error in your project. to do this the compiler needs to check all files do not have errors, which is in fact the majority of the time for emit.

i would suggest not setting the flag if you are doing incremental builds.