plain.js

'use strict';

var callable      = require('es5-ext/object/valid-callable')
  , forEach       = require('es5-ext/object/for-each')
  , extensions    = require('./lib/registered-extensions')
  , configure     = require('./lib/configure-map')
  , resolveLength = require('./lib/resolve-length')

  , hasOwnProperty = Object.prototype.hasOwnProperty;

module.exports = function self(fn/*, options */) {
	var options, length, conf;

	callable(fn);
	options = Object(arguments[1]);

	// Do not memoize already memoized function
	if (hasOwnProperty.call(fn, '__memoized__') && !options.force) return fn;

	// Resolve length;
	length = resolveLength(options.length, fn.length, options.async && extensions.async);

	// Configure cache map
	conf = configure(fn, length, options);

	// Bind eventual extensions
	forEach(extensions, function (fn, name) {
		if (options[name]) fn(options[name], conf, options);
	});

	if (self.__profiler__) self.__profiler__(conf);

	conf.updateEnv();

  // expose conf to the user application so that on('event') could be
  // called externally
  var memoized = conf.memoized;
  Object.defineProperty(memoized, 'config', {
    value: conf,
    __proto__: null
  });
  return memoized;
};