> In the real world, it turns out that code you didn't write can also have bugs or not behave as you expect it to, so the less of that there is, the better.

jQuery's not a very good example of this though. It's one of the most widely used, and hence most tested and least buggy pieces of software out there. Nowadays the web APIs are pretty solid, but back in the IE6/7/8 days the jQuery API was a lot less buggy than using the built in APIs directly.

Have fun implementing everything from scratch in assembly.

> In the real world... From experience...

Does jQuery (est. 2006) have more bugs in it than your code?

As has been seen many times recently third party libraries are a major attack vector for the bad guys.

> In the real world, it turns out that code you didn't write can also have bugs or not behave as you expect it to

To me this seems a comment that only stands for one-developer projects.

Good point. This is what I was referring to:

https://en.wikipedia.org/wiki/Encapsulation_(computer_progra...