Is it permissible to use part of the source code, under mit license?

Question

Copyright

For example, there is one library. There is some functionality that I really liked.
I know that I can absolutely legally take and remake it for myself simply by indicating authorship.
But is it worth it if I take and put this piece of code for myself. Approximately around 500-800 lines of code?
I could write it myself, but I will not find the best result. Is it worth it to invent something of your own?

Answer 1

500-800 lines of code is nothing (especially when it comes to loose JavaScript code).
Go through it with powerful refactoring with renaming of all identifiers, spread the logic of functions over several functions, turn out all the class methods, set up new classes and wrap the pieces that turned out to be outside. Everything will take a couple of hours. What eventually remains of the code, the mother will not know.

Answer 2

Yes, do not suffer, take what you need, the main issue is ethical, not legal.