什么是Node.js post方法中的第二个参数 [英] What is second parameter in nodejs post method

问题描述

在我的代码中，我编写了这样的代码

In my code I have code written like this

 router.post('/', publicShare, function(req, res, next) {

我签入了文档，但没有找到第二个参数publicShare的原因?

I check in documents but not found why second param publicShare is here?

publicShare看起来像

var publicShare = function(req, res, next) {
    if (condition1) {
        if (condition2) {
            res.status(400).send({success:false});
        } else {
            next();       
        }
    } else {
        if (condition3) {
            res.status(401).send({success:false});
        } else
            next();
    }
};

请帮助我理解.

推荐答案

您可以检查

You can check route handlers which accepts array of callbacks which just behaves like a middleware. Example from the docs:

app.get('/example/d', [cb0, cb1], function (req, res, next) {

因此，在您的情况下，publicShare可以是回调数组，也可以是签名只是接受req，res和next作为参数的回调的回调.因此，您也可以像这样使用:

So, in your case publicShare can be array of callbacks or just a callback which signature is just a callback accepting req, res, and next as parameter. So, you can also use like:

app.get('/', function(req, res, next){}, function(req, res, next){}, ...

为了简单起见，您将使用回调数组:

And for easier, you would use an array of callbacks:

app.get('/',[cb1, cb2, cb3])

其中cb1，cb2和cb3是带有请求，响应和下一个参数的回调.它允许您一个一个地运行. cb1->执行日志1，然后cb2->执行日志2，cb3->执行日志3，依此类推.

Where cb1, cb2, and cb3 are the callbacks with request, response and next parameters. It allows you to run one by one. cb1 -> do log 1, then cb2 -> do log 2, cb3 -> do log 3 and so on.

我将通过一个示例来简化此操作:

您要喝水.

1)cb1:购买一瓶水.

1) cb1: Purchase a jar of water.

2)cb2:在水桶或广口瓶中加入几滴水.

2) cb2: Add few water drops in the bucket or jar.

3)cb3:将其煮沸.

3) cb3: Boil it.

然后，轮到您了.喝！

这篇关于什么是Node.js post方法中的第二个参数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！