Example of lazy evaluation in JavaScript?

es6.js

const add = a => b => () => a() + b();
const one = () => 1
add(add(one)(one))(one)(); // 3

LazyEvaluation.js

add = function (a) {
  return function (b) {
    return function () {
      a = a();
      b = b();
      return a + b;
    };
  };
};
one = function () {return 1;};
add(add(one)(one))(one)(); // 3