Include memory usage in -diagnostics report

[ahejlsberg]

The -diagnostics command line switch now includes memory usage in the reported statistics when running under node.js. If node.js was invoked with the -expose-gc flag, global.gc() is called before obtaining the allocated heap size to get a more accurate number. For example:

node -expose-gc tsc -diagnostics myProgram.ts

Note that memory usage is not reported with the cscript.exe host since it provides no way to obtain memory statistics.

[mhegazy]

👍

[DanielRosenwasser]

getMemoryUsage returns 0 under WScript? This isn't documented well. I feel like we should either document the sentinel value (0 in this case, or potentially any negative value), or make getMemoryUsage an optional property that you check from sys, much like watchFile.

[vladima]

👍

[ahejlsberg]

@DanielRosenwasser Yes, makes more sense for sys.getMemoryUsage to be optional.

[DanielRosenwasser]

Thanks for addressing that! 👍