Overloading Javascript Functions

overload.js

const overload = (() => {
  const noop = () => {};
  const typeOf = (p) => (Object.prototype.toString.call(p).slice(8,-1));

  return (fns) => (function (...args) {
    const key = args.map(typeOf).join('_');
    return (fns[key] || noop).apply(this, args);
  });
})();


// USAGE EXAMPLE

let greet = overload({
  String: (name) => `Hi, ${name}!`,
  Array: (names) => `Hello ${names.join(', ')}!`,
  Number: (x) => `Welcome number ${x} :)`,
  Array_Function: (arr, f) => arr.map(f)
});

console.log(greet('Tom'))
//=> "Hello Tom"

greet(['Alice', 'Bob', 'Carol']);
//=> "Hello Alice, Bob, Carol!"

greet(6);
//=> "Welcome number 6 :)"

greet(['Dave', 'Eve', 'Frank'], (name) => `${name} is here!`);
//=> ["Dave is here!", "Eve is here!", "Frank is here!"]