We want to create a function that will add numbers together when called in succession.
add(1)(2); //3
We also want to be able to continue to add numbers to our chain.
add(1)(2)(3); // 6
add(1)(2)(3)(4); // 10
add(1)(2)(3)(4)(5); // 15
and so on.
A single call should return the number passed in.
add(1) // 1
and we should be able to store the result and reuse it.
const addTwo = add(2);
addTwo // 2
addTwo + 5 // 7
addTwo(3) // 5
addTwo(3)(5) // 10
We can assume any number being passed in will be valid javascript number.