Good news. Compiler performance is pretty horrible at scale.
I hope that they implement in-memory compilation, so that the compiler can work properly with Gulp (which would also increase build times). I also hope that they'll support automatic generation of ambient external declaration files. TypeScript doesn't work well with npm modules just yet because of that.
About TypeScript+Gulp: I was using gulp-tsc, but switched to gulp-type (https://www.npmjs.org/package/gulp-type). It offers incremental compilation and you can disable chasing through all references in the sourcefiles (since with Gulp you already provide all sources in the stream). This sped up our re-compilation times three-fold.
The really slow compiler performance was quite surprising. I switched back to coffeescript (then eventually switched to ScalaJs where they are much faster) because they were so long.
>I hope that they implement in-memory compilation, so that the compiler can work properly with Gulp
In-memory compilation already exists. I wrote a Gulp wrapper for TS for my own project [0] that supports both normal compilation and incremental compilation (i.e., watch functionality).
The real issue with TS is that it doesn't export a programmable compiler API by default, necessitating either a process.exec to the shell script or adding an export statement using the vm module. I gather that was a low priority for the devs because they wanted to get the compiler API in shape first.
Well, it seems that it requires quite a lot of code. Perhaps you should publish the gulp wrapper as a Gulp plugin.
By the way, does your Gulp wrapper load files from the disk, or are the files given to it as in-memory streams? That's what I mean by "in-memory compilation".
>does your Gulp wrapper load files from the disk, or are the files given to it as in-memory streams
The latter. The TS compiler (TypeScriptCompiler) internally works with string sources and outputs strings. The official sources use a wrapper around it (BatchCompiler) that converts input file names to input file contents and output JS+sourcemaps to files. My wrapper uses file contents from gulp.src for the same.
>Well, it seems that it requires quite a lot of code
Yes. The first part of my code is basically a reimplementation of BatchCompiler. But my code also does other things - for example I fiddle with the AST to generate automatic JSDocs, etc.
I hope that they implement in-memory compilation, so that the compiler can work properly with Gulp (which would also increase build times). I also hope that they'll support automatic generation of ambient external declaration files. TypeScript doesn't work well with npm modules just yet because of that.