This isn't meant for teaching new material; just to jog your memory when you can't remember something small about any given method.
If you have a console in your text editor, feel free to replace the console.log() lines with debug().
These were written in repl.it. You can copy, paste, and run the scripts from there.
If there are bugs, or better ways to implement these functions, then feel free to fork and submit a pull request. Improvements are welcome.