ch4: fixing compose implementation bug

[darkamenosa]

This commit fixes #146

[getify]

Thanks for finding and fixing this bug.

However, rather than fixing this with slice(), I'd rather fix it by saying [...fns].reverse().reduce(..) (still all on one line, for layout reasons). And btw, this code is repeated/quoted in chapter 9, so it needs to be fixed there, too. :)

Also, in chapter 9, about a page after that reference, fns.reverse().reduce(..) is quoted again, in a paragraph, so that should be updated, as well.

[darkamenosa]

I have changed the implementation follow your recommendation and updated chapter 9. Thanks for reminding me.

[DScheglov]

Hi, I guess if we are using spread to splice the array, so we could use the reduceRight to avoid reverse and slice at all, am I wrong? :)

@getify, thanks a lot for the Book.

[getify]

@DScheglov this is intentionally not done here because we come back to the topic of compose(..) in ch9 when we talk about list operations, and we illustrate reduceRight(..) there.

[getify]

Thanks so much!