Bulk monoid

Bulk.js

/*

- Goal: 
  implmenting something like Pair(a, b) but could accommodate any amount of arguments

- Usage: 
  
  Bulk( Sum(2), Sum(3), Sum(4) )
  .concat(Bulk(Sum(1), Sum(1), Sum(1)))
  
  Bulk( Sum(2), Sum(3), Sum(4), Sum(5) )
  .concat(Bulk(Sum(1), Sum(1), Sum(1), Sum(1)))

- Question 1: What if the arguments count aren't the same? Ex:
  
  Bulk( Sum(2), Sum(3), Sum(4) )
  .concat(Bulk(Sum(1))) // 3 vs. 1 arguments

- Question 2: What if argument type doesn't match? Ex: 
  
  Bulk( Sum(2), Sum(3) )
  .concat(Bulk(All(1), First(1)))
  
*/
const Bulk = (...xs) => ({
	xs,
	concat: ys => Bulk(...xs.map((x, idx) => x.concat(ys.xs[idx]))),
	bulkMap: (...fs) => Bulk(...xs.map((x, idx) => fs[idx](x))),
	toList: _ => xs,
})