Category theory for JavaScript programmers #4: functors

[MikeStay]

JavaScript functions are used for nearly everything: objects, morphisms, categories, functors, natural transformations, etc.

[wieslawpopielarski]

Mike,
I see you added 3 next lessons :). Cool, first I have to understand that what you present in first 24 lessons. So now I'm walking there and back. I try to catch if the functor is a function or the function can be both object and morphism. I guess it is. Continue struggling.

[joejoe-lbbw]

There is in ECMAScript 5 the Array.isArray( x) function, it addresses the multiple globals in browser.