Passing route control with optional parameter after root in express

Question

I m working on a simple url-shortening app and have the following express routes   app get      function req  res     res render  index         link  null            app post      function req  res     function makeRandom        var text           var possible    ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789        for  var i 0  i  lt  3   y u looking at me  lt 33      i           text    possible charAt Math floor Math random     possible length        return text        var url   req body user url    var key   makeRandom      client set key  url     var link    http   50 22 248 74 l     key    res render  index         link  link         console log url     console log key        app get   l  key   function req  res     client get req params key  function err  reply       if client get reply          res redirect reply             else        res render  index             link  null                             I would like to remove the  l  from my route  to make my url s shorter  and make the  key parameter optional   Would this be the correct way to do this   app get    key    function req  res  next     client get req params key  function err  reply       if client get reply          res redirect reply             else        next                     app get      function req  res     res render  index        link  null             Not sure if I need to specify that my   route is the one to be  nexted  to   But since my only other route would be my updated post   route  I would imagine it would work fine

User · Accepted Answer

That would work depending on what client.get does when passed undefined as its first parameter.

Something like this would be safer:

app.get('/:key?', function(req, res, next) {
    var key = req.params.key;
    if (!key) {
        next();
        return;
    }
    client.get(key, function(err, reply) {
        if(client.get(reply)) {
            res.redirect(reply);
        }
        else {
            res.render('index', {
                link: null
            });
        }
    });
});

There's no problem in calling next() inside the callback.

According to this, handlers are invoked in the order that they are added, so as long as your next route is app.get('/', ...) it will be called if there is no key.

User · Answer

Express version     dependencies          body-parser     1 19 0        express     4 17 1        Optional parameter are very much handy  you can declare and use them easily using express   app get   api v1 tours  cId  pId  batchNo     req  res   gt       console log  category Id    req params cId       console log  product ID    req params pId       if  req params batchNo           console log  Batch No    req params batchNo               In the above code batchNo is optional  Express will count it optional because after in URL construction  I gave a     symbol after batchNo    batchNo    Now I can call with only categoryId and productId or with all three-parameter   http   127 0 0 1 3000 api v1 tours 5 10   or http   127 0 0 1 3000 api v1 tours 5 10 8987

[node.js] Passing route control with optional parameter after root in express?

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