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JavaScript

Posted by Laurence kite
Laurence kite
11,768 Points

express error message: Can't set headers after they have been sent

I am following express basics by Andrew Chalker and all was going well until adding the the card.js file for random cards and typing a number to get a card..

Although the app still runs and the card is displayed on the page as expected I get an error in the terminal program every time a certain route is accessed that has a res.redirect in it.

I thought it was me and probably is, but I download the code and paste it in for all Javascript files but the error is not going away.. I am not sure if its because he is using an older version of express or what it is.. 

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

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

});

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;
Ben Newton
Ben Newton
14,726 Points

I see this error too, I'm at the point where I'm adding the 'next card' link. Everything actually works fine, but this error presents every-time we go through the route of '/cards/' which inturn redirect to '/cards/:id'