Currying but with an options object!

option-curry.js

var curry = (function() {

  return curry;

  function isObject(thing) {
    return Object(thing) === thing;
  }
  
  function isEmpty(object) {
    return isObject(object) && ! Object.keys(object).length;
  }
  
  function satisfies(contract, object) {
    return Object.keys(contract)
      .reduce(function(yes, key){
        var wrapped = Object(object);
        return yes
          && wrapped.hasOwnProperty(key)
          && (isObject(contract[key]) 
                ? satisfies(contract[key], wrapped[key])
                : true);
      }, true);
  }
  
  function clone(object) {
    return isEmpty(object) ? {} : merge({}, object);
  }
  
  function merge(target, options) {
    return Object.keys(options)
      .reduce(function(copy, key){
        copy[key] = isObject(options[key])
          ? merge({}, options[key])
          : options[key];
        return copy;
      }, clone(target));
  }
  
  function curry(fn, contract) {
    return function func(options) {
      if (! satisfies(contract, options)) {
        return function inner(innerOptions){
          return func.call(this, merge(options, innerOptions));
        };
      } else {
        return fn.call(this, options);
      }
    }
  }
  
})();