JavaScript Express Basics Parameters, Query Strings, and Modularizing Routes Linking Around the Application

Karen Shea
Karen Shea
13,731 Points
Posted by Karen Shea
Karen Shea
13,731 Points

RangeError [ERR_HTTP_INVALID_STATUS_CODE]: Invalid status code: undefined Pretty sure the issue is in cards.js.

Pretty sure the issue is in cards.js.

Here is the entirety of that file:

```const express = require('express'); const router = express.Router(); const { data } = require('../data/flashcarddata.json'); const { cards } = data;

router.get('/', (req, res) => { const numberOfCards = cards.length; const flashcardId = Math.floor(Math.random() * numberOfCards); res.redirect(/cards/${flashcardId}); });

router.get('/:id', (req, res) => { const { side } = req.query; const { id } = req.params;

if (!side) { res.redirect(/cards/${id}?side=question) } const name = req.cookies.username; const text = cards[id][side]; const { hint } = cards[id];

const templateData = { id, text, name };

if (side === 'question') {
    templateData.hint = hint;
    templateData.sideToShow = 'answer';
    templateData.sideToShowDisplay = 'Answer';
} else if (side === 'answer') {
    templateData.sideToShow = 'question';
    templateData.sideToShowDisplay = 'Question';
}

res.render('card', templateData);

});

module.exports = router;```

2 Answers

Marie Franklin
Marie Franklin
11,488 Points
Marie Franklin
Marie Franklin
11,488 Points

One problem is that you are defining side as const and later reassigning it... instead you should define side with let

    let {side} = req.query;
Kevin Gates
Kevin Gates
14,701 Points
Kevin Gates
Kevin Gates
14,701 Points

Okay, I've had to deal with this. It's requiring an HTTP status code, so I've used 302. So if you change from this:

res.redirect(/cards/${flashcardId});

to this

res.status(302).redirect(`/cards/${flashcardId}`);

it should work.

Also though, for me the behavior is different. If I'm in the sub-folder already it sometimes results in cards/cards/3...

So to get this to work localhost:3000/cards/ and localhost:3000/cards/3 to work, I need to make my code this:

const express = require('express');
const router = express.Router();
const { data } = require('../data/flashcardData.json');
const { cards } = data;

router.get('/:id', (req, res) => {
    const { side } = req.query;
    const { id } = req.params;

    if ( !side ) {
        res.status(302).redirect(`${id}?side=question`)
    }

    const text = cards[id][side];
    const { hint } = cards[id];

    const templateData = { id, text };
    if (side === 'question') {
        templateData.hint = hint;
        templateData.sideToShow = "answer";
        templateData.sideToShowDisplay = "Answer";
    } else if (side === "answer") {
        templateData.sideToShow = "question";
        templateData.sideToShowDisplay = "Question";
    }
    res.render('card', templateData);
});

router.get('/', (req, res) => {
    const totalCards = cards.length;
    const randomCard = Math.floor(Math.random()*totalCards);
    res.status(302).redirect(`${randomCard}?side=question`);
});


module.exports = router;