How to use merge-descriptors - 6 common examples

const requestJar = request.jar();
  const requestObj = request.defaults({ jar: requestJar, ...config });
  setPrototypeOf(requestObj, requestJar);

  // Crawler base:
  const crawler: Object = {
    base: base,
    opts: config,
    req: SpiderRequest,
    res: SpiderResponse,
    request: requestObj
  };

  // Glues all the components together:
  mixin(crawler, SpiderQueue, false);
  mixin(crawler, SpiderRouter, false);
  mixin(crawler, EventEmitter.prototype);

  return crawler;
}

// Will be used by retry-request:
  const requestJar = request.jar();
  const requestObj = request.defaults({ jar: requestJar, ...config });
  setPrototypeOf(requestObj, requestJar);

  // Crawler base:
  const crawler: Object = {
    base: base,
    opts: config,
    req: SpiderRequest,
    res: SpiderResponse,
    request: requestObj
  };

  // Glues all the components together:
  mixin(crawler, SpiderQueue, false);
  mixin(crawler, SpiderRouter, false);
  mixin(crawler, EventEmitter.prototype);

  return crawler;
}

callActions(uri: string, req: Object, res: Object): void {
    for (const index in this.callbacks) {
      const parameters: Object = wildcard(uri, index);
      const callback: Function = this.callbacks[index];

      if (uri === index || parameters) {
        // Merge request parameters with wildcard output:
        // NOTE: pheraps we should override params on each callback?
        mixin(req.params || {}, parameters || {});

        callback({ req, res, uri });
      }
    }
  }
};

const requestObj = request.defaults({ jar: requestJar, ...config });
  setPrototypeOf(requestObj, requestJar);

  // Crawler base:
  const crawler: Object = {
    base: base,
    opts: config,
    req: SpiderRequest,
    res: SpiderResponse,
    request: requestObj
  };

  // Glues all the components together:
  mixin(crawler, SpiderQueue, false);
  mixin(crawler, SpiderRouter, false);
  mixin(crawler, EventEmitter.prototype);

  return crawler;
}

constructor(context = {}, settings = {}) {
    super();
    this.originalApp = application;
    mixin(this, omit(this.originalApp, ['listen']), false);
    this.init();
    this.request = request;
    this.request.app = this;
    this.response = response;
    this.response.app = this;
    Object.assign(this.request, context);
    this.merge(settings);
  }

    (dest, src, i) => mergeDescriptors(dest, src, redefine),
    args[0],