Poor man's Ramda, dependent on underscore.js

r.js

// Dependencies
// _

// Some helper functions to be used in composition, inspired by Ramda
window.r = (function(_) {
  var curry,
    flip2,
    invoke,
    split,
    map,
    drop;

  // (* -> a) -> (* -> a)
  // Returns a curried equivalent of the provided function
  curry = function(fn) {
    var context = this;

    return function wrapped() {
      var arity = fn.length;

      var later = function() {
        var args = _.toArray(arguments);

        if (args.length >= arity) {
          return fn.apply(context, args);
        } else {
          return function() {
            var accumulatedArgs = args.concat(_.toArray(arguments));
            return later.apply(context, accumulatedArgs);
          };
        }
      };

      return later.apply(context, _.toArray(arguments));
    };
  };

  // (a -> b -> c) -> (b -> a -> c)
  // Returns a function with the two arguments flipped
  flip2 = curry(function(fn) {
    var context = this;

    return function(a, b) {
      return fn.apply(context, [b, a]);
    };
  });

  // (* -> a) -> * -> Object -> *
  // Invokes function with arguments and context
  invoke = function(fn) {
    return function() {
      var args = _.toArray(arguments);

      return function(target) {
        return fn.apply(target, args);
      };
    };
  };

  // (String | RegExp) -> String -> [String]
  // Splits a string into an array of strings based on the given separator.
  split = invoke(String.prototype.split);

  // (a -> b) -> [a] -> [b]
  // Map a transformation function over a collection
  map = curry(flip2(_.map));

  // Number -> String -> String
  // Drops the first n characters of the string
  drop = curry(function(num, str) {
    return str.substring(num);
  });

  return {
    flip2: flip2,
    curry: curry,
    split: split,
    map: map,
    drop: drop,
    compose: _.compose
  };
})(_);