Not sure why the card is not showing.

extends app

block card
  section(class=`flashcards`)
    .card(class=`card-${side}`)
      .card-header
      h1.card-title= side
      #content
        h2= text
        if hint
          p.hint
            i= hint
      .card-flip-wrap
        a(href=`${id}?side=${sideToShow}`)
          img.card-flip(src='/static/img/flip.svg')
      .card-next
        a(href='/cards')
          img(src="/static/img/next.svg")
    script(src='/static/js/app.js')

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) {
    return 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;