Added support for async fitness function using Promises

[richardklafter]

Minimal changes to support async fitness fitness functions with promises.

[zinefer]

Does this run my fitness functions in parallel? How could I check something like that...

[richardklafter]

It runs all the fitness functions from one generation in parallel. If your fitness function is 100% JS this will not speed anything up but if your fitness function makes network calls or preforms some other async operation they will all be done in parallel.

I used it for tuning the parameters of an AI I built to play a game. In that case, running my fitness function took ~3min and I did it on lots of remote servers.

[zinefer]

Yeah, I came to that realization a bit later last night. My fitness function is just javascript that will require some engineering to get to run asynchronously. Thanks for your help.

[Glavin001]

For those looking for async support, I've forked this repo and rewrote it in TypeScript and added support for async fitness method (including unit tests): https://github.com/Glavin001/genetic-js
Hope this helps you, too! 😃