Pass a variable to view in every request, Node.js Express

Question

I have some code that is repeated among my routes, and I always pass to the view some resulting variables from that repeated code.

Example:

/* GET /events/list */
router.get('/events/list', function(req, res) {

  var blah = someFunctionThatAnalyzesUserCookie();

  res.render('places/list', { title: 'Places', blah: blah });
});

/* GET /events/details */
router.get('/events/details', function(req, res) {

  var blah = someFunctionThatAnalyzesUserCookie();

  res.render('places/details', { title: 'Some place', blah: blah });
});

How can I refactor this?
I need to pass blah to all of my views and I want their logics clean, like this:

/* GET /events/list */
router.get('/events/list', function(req, res) {

  res.render('places/list', { title: 'Places' });
});

/* GET /events/details */
router.get('/events/details', function(req, res) {

  res.render('places/details', { title: 'Some place' });
});

I googled for a while but only found how to execute something in every request, like this:

app.use(function(req, res, next) {

    doSomethingInEveryRequest();

    next();
});

But I can't figure out how to pass a variable to the view in every request.

Also I read about app.locals, but I guess that is more suited for constants. My passed variable depends on the user's cookies so is a... variable.

can you try extracting a function with two parameters path, renderFileName & title? — Mritunjay
– Mritunjay, Commented Jul 18, 2014 at 4:29
hummm I don't understand the idea that you are suggesting. What is renderFileName? Also i should point out that some of these methods pass the title and some pass more data... but they always pass blah — sports
– sports, Commented Jul 18, 2014 at 4:31

Mritunjay · Accepted Answer · 2014-07-18 04:35:54Z

2

Can you try something like bellow:-

var renderPage = function(path,fileName,title){
    router.get(path,function(req,res){
        var blah = someFunctionThatAnalyzesUserCookie();
        res.render(fileName,{title:title, blah:blah});
    });
}

renderPage('/events/list','events/list','Places');
renderPage('/events/details','events/details','Some Place');

answered Jul 18, 2014 at 4:35

Mritunjay

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3 Comments

sports Over a year ago

that technique is called middleware?

Mritunjay Over a year ago

ohhhh you are asking, No I don't think so, I just re-factored the code to remove duplication.

sports Over a year ago

well I will mark it as accepted because you gave me the main idea of what I have to do. To make it clear for the rest of the world: instead of using res.render(viewPath, obj) at the end of every request, I will be using a custom method, renderPage, which at the end does use res.render(...) but with the opportunity there to alter every response. :p

ahoffer · Accepted Answer · 2014-07-18 04:32:59Z

0

I think you can use Express's middleware called "Cookie-Parser".

Here is a link to its documenation: https://github.com/expressjs/cookie-parser/blob/master/README.md

answered Jul 18, 2014 at 4:32

ahoffer

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