The question was closed as being too broad ("needs more focus"), not as being off-topic. Literally, the question is a "list of things" question, but since that list would probably be very short, maybe containing only one or two major points, I personally tend to disagree with the close voters here (and voted for reopening). However, closing and reopening is a community process. If you can convince 2 more reopen voters, your question might get reopened (or now, as it was deleted, to get undeleted).
To increase the chance for this, I would heavily recommend to improve the question by giving some examples of what you precisely mean by "hidden errors other than type errors". Currently, that part of your question seems to be a little bit blurry to me.
And don't say you need to be a typescript expert for doing so, that's would be a really bad excuse. You wrote "[for] C++ or Delphi, it seems far more errors are found" - so I am sure you could give us some examples of errors you have in mind.