We annihilate the need for the ol' nested for loop using Applicatives.

 

For example we have this kind of nested loop code:

for(x in xs){  for(x in ys){     for(z in zs){      }  }}

 

We can refactor it by using List comprehension:

const {List} = Immutable; const res1 = List.of(x => x).ap(List([1,2,3]));console.log(res1) // List [ 1,2,3 ]

 

const res1 = List.of(x => y=> `${x} - ${y}`)      .ap(List(['teeshirt', 'sweater']))      .ap(List(['large', 'medium', 'small']));console.log(res1) //List [ "teeshirt - large", "teeshirt - medium", "teeshirt - small", "sweater - large", "sweater - medium", "sweater - small" ]