gistfile1.js

/**
 * Sandbox
 *
 * Use Backbone Events to create a generic event handler.
 * http://backbonejs.org/#Events
 */
define([], function () {

  return {
    create: function (parent) {
      var sandbox = _.clone(Backbone.Events);

      // ==================================
      // Allow users of the sandbox to request a 'provided' piece of data.
      //
      // Takes an string identifier and a callback, which will be called with
      // the provided value or undefined if no provider for that identifier
      // is found.
      //
      // There can only be one provider for a given identifier.
      // ==================================
      sandbox.request = function (identifier, cb) {
        if (!this._providers) this._providers = {};

        var provider = this._providers[identifier];

        // Defer request upwards
        if (!provider && parent) return parent.request(identifier, cb);

        if (typeof provider === 'function') {
          return provider(cb);
        }

        return cb(provider);
      };

      // ==================================
      // Provide a piece of information to users of the sandbox either via a
      // raw value or via a callback.
      //
      // Takes a string identifier and a provision, which is any kind of data.
      // If the provision is a function is will be called and passed a callback
      // which it should call with the provided data.
      //
      // There can only be one provider for a given identifier.
      // ==================================
      sandbox.provide = function (identifier, provision) {
        if (!this._providers) this._providers = {};
        this._providers[identifier] = provision;
      };

      sandbox.log = window.console.log.bind(console);

      return sandbox;
    }
  };

});