Node.js表达：中间件工厂

Question

我正在尝试使用express在node.js api服务器中编写中间件工厂。

export function argMiddlewareFactory(args: any[]) 
  const middleware = async (
    req: Request,
    res: Response,
    next: NextFunction
  ) => 
    for (let arg of args) 
      console.log("inside argMiddlewar");
      console.log(arg);
      if (!req.body.hasOwnProperty(arg)) 
        let errorMessage: string = `Following property is required: $arg`;
        res.status(400).send(errorMessage);
      
    
    next();
  ;
  return middleware;

此函数应接受键数组（后请求所要求，并返回中间件）。例如：

requiredArgs: string[] = ["email","password"];

const credentialMiddleware = argMiddlewareFactory(requiredArgs)

router.use(credentialMiddleware)

问题是当我启动服务器时出现此错误：

TypeError: argMiddlewareFactory is not a function at Object.<anonymous> 

  at Module._compile (internal/modules/cjs/loader.js:778:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:789:10)
    at Module.load (internal/modules/cjs/loader.js:653:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
    at Function.Module._load (internal/modules/cjs/loader.js:585:3)
    at Module.require (internal/modules/cjs/loader.js:692:17)
    at require (internal/modules/cjs/helpers.js:25:18)
    at Object.<anonymous> (/home/linux/Progetti/Private/ecommerce-cartoleria/Code/product-service/server/build/src/index.js:23:21)
    at Module._compile (internal/modules/cjs/loader.js:778:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:789:10)
    at Module.load (internal/modules/cjs/loader.js:653:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
    at Function.Module._load (internal/modules/cjs/loader.js:585:3)
    at Function.Module.runMain (internal/modules/cjs/loader.js:831:12)
    at startup (internal/bootstrap/node.js:283:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:623:3)

您能解释为什么吗？