It seems to me the author should think twice about rewriting an entire code base in a new language. This almost always leads to disaster, and often doesnt give you a lot of value.

Also he is pointing out, that he doesnt want to use 3rd party libraries. I worked with people who said that before... This breaks the whole idea of writing software by standing on the shoulders of giants. When you write an app, you almost ALWAYS use libraries (and they are not written by you). Writing a complete app just with the core language tools seems like total nonsense to me.. Why woudnt you use a library that solves the job for you?

You should off course try to prevent entangling dependency of a lib into your code base. But thats a basic rule of software engineering.

B.t.w, with testing, you can mock away those libraries and still have nice unit tests.