Write a function that takes a binary function, and makes it callable with two invocations

binary _function_with_two_invocations.js

function applyf(binary) {
  return function(x) {
    return function(y) {
      return binary(x, y);
    };
  };
}

addf = applyf(add);
addf(3)(4) //=> 7
applyf(mul)(5)(6) //=> 30