How can I make var a = add(2)(3); //5 work?

Question

I want to make this syntax possible:

var a = add(2)(3); //5

based on what I read at http://dmitry.baranovskiy.com/post/31797647

I\

Answer 1

This will handle both

add(2,3) // 5

or

add(2)(3) // 5

This is an ES6 curry example...

const add = (a, b) => (b || b === 0) ? a + b : (b) => a + b;