Coffeescript隐含的回报对性能和副作用产生影响(Coffeescript implicit returns impact on performance and side effects)

 我目前正在开发一个使用Express.js和Mongoose的node.js Web服务。 最近，我想我会尝试使用CoffeeScript，因为我听说有一些好处。 但是，我注意到了一些有点令人不安的事情，我很好奇是否有人可以澄清。 
 
 这是我在普通javascript中的一条路线： 
 
router.post('/get/:id', decorators.isManager, function(req, res) {
    Group.findById(req.params.id, function(err, grp) {
            if(err) res.status(500).end();
            if(grp == null) res.status(500).send('The group could not be found');
            res.send(grp);
    });
});
 
 但是，使用以下（几乎相当于coffeescript）： 
 
router.post '/get/:id', decorators.isManager, (req, res) ->
  Group.findById req.params.id, (err, grp) ->
    res.status(500).end() if err
    res.status(500).send 'The group could not be found' if not grp?
    res.send grp
 
 将此重新编译为javascript会返回以下内容： 
 
router.post('/get/:id', decorators.isManager, function(req, res) {
    return Group.findById(req.params.id, function(err, grp) {
            if(err) res.status(500).end();
            if(grp == null) res.status(500).send('The group could not be found');
            return res.send(grp);
    });
});
 
 这些额外的回报会影响我的应用程序的性能吗，它会改变它的工作方式吗？ 我测试了它，似乎是相同的响应时间但是我不确定这会对多个嵌套查询产生什么影响。 谢谢！ 

I am currently working on a node.js web service which utilizes Express.js and Mongoose. Recently, I figured I would try my hand at CoffeeScript, as I have heard that there are some benefits to be had. However, I have noticed something a little unsettling, and I was curious if someone could clarify.
 
Here is one of my routes in plain javascript:
 
router.post('/get/:id', decorators.isManager, function(req, res) {
    Group.findById(req.params.id, function(err, grp) {
            if(err) res.status(500).end();
            if(grp == null) res.status(500).send('The group could not be found');
            res.send(grp);
    });
});
 
However, with the following (nearly equivalent coffeescript):
 
router.post '/get/:id', decorators.isManager, (req, res) ->
  Group.findById req.params.id, (err, grp) ->
    res.status(500).end() if err
    res.status(500).send 'The group could not be found' if not grp?
    res.send grp
 
Re-compiling this to javascript returns the following:
 
router.post('/get/:id', decorators.isManager, function(req, res) {
    return Group.findById(req.params.id, function(err, grp) {
            if(err) res.status(500).end();
            if(grp == null) res.status(500).send('The group could not be found');
            return res.send(grp);
    });
});
 
Will those extra returns effect the performance of my application, does it alter the way it works? I tested it, it seems to be the same response time however I am not sure the impact this will have on multiple nested queries. Thank you!

原文：https://stackoverflow.com/questions/29070113