JS implementation of curry function with some ES6 sugar.

curry.js

function curry(fn) {
  
  const arity = fn.length;
  
  const curring = function() {
    
    var args = asArray(arguments);

    if (args.length >= arity) {
      return fn(... args);
    }
    
    return function() {
      return curring(... args.concat(asArray(arguments)));
    };
  }
  
  const asArray = parameters => Array.prototype.slice.call(parameters, 0);
  
  return curring;
}