Make the syntax work sum(1)(2)(3).......() [Asked in multiple interviews]

curry-sum-arity.js

function sum(a) {
	return function(b) {
		if(b){
			return sum(a+b);
		}
		return a;
	}
}


/* ES 6 Version of the code */

// sum => a => b => b ? sum(a+b) : a; 

sum(1)(2)(3)(4)(5)();