如何在Node中创建可重用的函数而不编写样板代码

I am using Express.js as http server. Defined all my routes.

我使用Express.js作为http服务器。定义了我的所有路线。

Most endpoints need to verify session before returning a response. E.g. below code serves users in the system and list of services respectively:

大多数端点需要在返回响应之前验证会话。例如。下面的代码分别为系统中的用户和服务列表提供服务:

function getUsers(req, res, next) {
  verifyUser(req, res, next, function () {
      //serve users
  });
}

function getServices(req, res, next) {
  verifyUser(req, res, next, function () {
    //serve services
  });
}

You probably noticed there is a verifyUser function which validates the session. Which is as below.

您可能已经注意到有一个验证会话的verifyUser函数。如下所示。

function verifyUser(req, res, next, callback) {
  var sessionKey = req.cookies.sessionKey;
  var user = users.userBySession(sessionKey);
  if (user) {
    callback(req, res, next, user);
  } else {
    res.status(401).send({
      message: 'Unauthorized'
    });
  }
}

As you can see I keep passing in req, res and next parameters along with a callback whenever I use this function.

正如您所看到的,每当我使用此函数时,我会继续传递req,res和next参数以及回调。

I tried to use apply function to make it easier. Changed my getUsers function like this:

我尝试使用apply函数使其更容易。改变了我的getUsers函数,如下所示:

function getUsers(req, res, next) {
  verifyUser
    .apply(null, arguments, function () {
      //serve users
    });
}

The problem with this approach is callback is not passed into verifyUser function. And I don't really like passing null as scope with each call.

这种方法的问题是回调没有传递给verifyUser函数。而且我不喜欢在每次调用时将null作为范围传递。

How can I achieve this by writing less and better code ? Any ideas?

如何通过编写更少和更好的代码来实现这一目标?有任何想法吗?

2 个解决方案

#1

You could use bind to create a 'partial function':

您可以使用bind来创建“部分函数”:

// create bound responseHelper object
var responseHelper = verifyUser.bind(null, req, res, next);

// usage
responseHelper(getUsersCallback); // same as verifyUser(req, res, next, getusersCallBack);

2 个解决方案

#1

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