I am using Node.js Tools for Visual Studio.
When I am opening a project it will take some time to load, because of Node.js analysis process.
Another problem is .ntvs_analysis.dat is growing larger and larger?
What is it and do I need it?
To my understanding, the NTVS extension analyzes your code to provide IntelliSense support. The result of the analyzed code is stored in ntvs_analysis.dat. However, it doesn't only analyze your code but also all installed npm_modules and their dependencies (and theirs, and theirs)). So installing more modules will make your ntvs_analysis.dat grow really fast.
There is an open issue on github https://github.com/Microsoft/nodejstools/issues/88 about this. The file is getting really big for some people including myself.
One proposed solution in the discussion is to reduce the depth of scanned folders. Turning off IntelliSense would help keeping the file smaller according to the discussion.