A core feature of Visual Studio that allows developers to inspect, analyze, and troubleshoot code during execution.
Problem was down to simple bad programming and also lack of help from VS.
I reported in and now VS gives syntax errors.
This helps a lot but node still crashes out a lot even if no syntax errors.
The trick seems to be incrementally change code and run it to see if what you have done causes a crash.
If you change a lot of code and it crashes the bug could be anywhere !