Simple currying function.

curry.js

/**
 * toArray :: ArrayLike => Array
 */

const toArray = (arrLike) => [].slice.call(arrLike, 0);

/**
 * Currying a function
 */

const curry = (fn) => {
  const newContext = (args) => {
    return function run() {
      const newArgs = args.concat(toArray(arguments));
      return newArgs.length === fn.length
        ? fn.apply(fn, newArgs)
        : newContext(newArgs);
    };
  };
  return newContext([]);
};

    function compose () {
        var fns = toArray(arguments);
        if (fns === 0) return;
        if (fns.length === 1) {
            return function () {
                var fn = fns[0];
                return fn.apply(fn, arguments);
            }
        } else {
            return function () {
                var rest = compose.apply(
                    compose,
                    fns.slice(1)
                );
                return fns[0](
                    rest.apply(rest, arguments)
                );
            };
        }
    }