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JavaScript Express Basics Parameters, Query Strings, and Modularizing Routes Using Data and Route Parameters

Posted by Reid Young
Reid Young
Courses Plus Student 14,209 Points

Now what about a route without an id?

Now that the route is variable and dependent upon a user added id to the end of the URL, e.g. localhost:3000/cards/0, how can we fix the application so that it runs if there is no id appended by the user to the URL?

I've written

router.get('/:id', (req, res) => { res.render('card', { if (req.params.id = undefined){ res.redirect('/0'); } prompt: cards[req.params.id].question, hint: cards[req.params.id].hint, answer: cards[req.params.id].answer }); });

which does not work. Now I'm confused. Thanks in advance for the help!

Kenneth Kim
Kenneth Kim
3,795 Points
Kenneth Kim
Kenneth Kim
3,795 Points

I'll just try to give my idea about it since i'm also learning this just now haha.

I believe if you do that, it should go the the default controller like the one with '/'. I think the best practice would be to provide a default controller for each route file that will handle the routing if there are no parameters in the request.

Maybe you could try adding 1 more route to the cards.js that can route the user to the Main menu or something like that. Something that it will be viewed as a default page if no parameter was given

Hope I was able to give you an idea or two :)

3 Answers

Tom Geraghty
Tom Geraghty
24,174 Points
Tom Geraghty
Tom Geraghty
24,174 Points

You could do this a few ways. I think the if statement works fine. My take was to just add a second route below the specific one where an ID is provided like this:

cards.js 
router.get('/:id', (req, res) => {
  res.render('card', { 
    cardFront: cards[req.params.id].question, 
    hint: cards[req.params.id].hint })
})

router.get('/', (req, res) => {
  res.render('card', { 
    cardFront: 'Default question', 
    hint: 'Default hint'
 })
})

This may be fine while developing, but thinking of a real flashcard app I would likely want either a list of cards for you to click on one to start at (using res.json(cards)), or just have the app start at card 0 every time cardFront: cards[0].question

Afdol Rizki
Afdol Rizki
23,158 Points
Afdol Rizki
Afdol Rizki
23,158 Points

hi, let me try to answer, i think you should move the if statement so it located before the response object instead of inside of it

wildgoosestudent
wildgoosestudent
11,274 Points
wildgoosestudent
wildgoosestudent
11,274 Points

This is probably what I would do (below is in pseudo code) 

// if there is no :id in the params || the number doesn't exist in our database
  // redirect to cards[0]
// else 
  //render the page it's asking for