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How do I show a HTML tag only when Express view engine passes a value?

Time:11-17

If you see the code below, you'll notice that for GET request, 'add' page does not get any value passed, whereas for POST request, 'add' page gets 'msg' value as a result of posting.

router.get('/add', (req, res) => {
  res.render('add', {})
})

router.post('/add', (req, res) => {
  // receive a form 
  // save it to the database
  // Promise is returned
  .then(gig => res.render('add', {
    msg: 'Your application is successful.'
  })
  .catch((err) => console.log(err));
  }
 })

In add.ejs file, I am not allowed to write <%= msg %> because it will cause an error for GET requests. Is there any other way than passing a { msg: null } to the GET router?

router.get('/add', (req, res) => {
      res.render('add', { msg: null })
})

I'm asking this because I think passing null for cases like this is very repetitive.

CodePudding user response:

the alternative would be adding a control in the file you want to render

<% var msg = msg ?? null %>

this way if the variable msg isn't passed the value is null and the field will be empty

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