SlowmoJS executes JavaScript in slow motion

Atul Varma describes his SlowmoJS as “an attempt to make learning JavaScript and computational thinking easier by making the execution of JS code more transparent.”

You give SlowmoJS a chunk of code and it shows each logical step of the code executing while highlighting the interesting bits and displaying the results.

I pasted in Ed Spencer’s FizzBuzz in a Tweet (slightly modified for brevity) and the resulting display is pretty cool. See for yourself.

The project’s source code, design notes, and implementation notes are available on GitHub.