method decorators.js

function requireAll (fn) {
  return function(...args) {
    if (fn.length === args.length) {
      return fn.apply(this, args);
    } else {
      console.error("All args are required")
      // throw new Error("All the arguments are required.");
    }
  }
}

const add = (a,b,c) => a + b + c;
const a = requireAll(add);
// console.log({ a: a.toString() })

console.log({ a: a(1,2,3,4) });
console.log({ b: a(1,2,3) }); // 6
console.log({ c: a(1) });
console.log({ d: a(1,2,7) });