Sorry for the delayed comment. But without further ado: WOW! This was like really impressive, I really liked the result and been studying it a lot. Couple of questions though, just to understand the rationale and standards, 1) why creating functions with the arrow functions? just to preserve the this object? 2) Why one function per step even though it would never (until now) be used again, for readability? 3) I thought one of the plus of Promises was the fact it doesn't need to declare variables out from its scope, so that let points; would never exist or am I really wrong?