Question 115267 in Mongodb Question posted in
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Mongodb – Getting error, Type Error : Cannot read properties of null (reading 'something') but still it works

I have a mongoDB database in which data is available when I use the ejs command <%=foundAnswer.week%> In the frontend the data gates printed but in the backend it posts error that cannot read null.. even though evrything works fine.

This is my backend route-

app.get('/nptel/:courseName/:weekNumber', function (req, res) {
  Nptel.findOne(
    {
      nptel_name: req.params.courseName,
      week: req.params.weekNumber,
    },
    (err, foundAnswer) => {
      if (!err) {
        res.render('nptel_weeksAnswer', {
          foundAnswer: foundAnswer,
        });
      } else {
        res.render('error');
      }
    }
  );
});

And here is the ejs file –

<div class="col"><h1>Week <%=foundAnswer.week%> :</h1></div>
<div class="nptel_answer mb-2">
   <div class="nptelQ"><h4><%=foundAnswer.question_1%></h4></div>
   <div class="nptelA"><h5><%=foundAnswer.answer_1%></h5></div>
</div>

Here, is the error –


TypeError: C:UsersparakDesktopMy WebsiteBrogrammersBrogrammersviewsnptel_weeksAnswer.ejs:5
    3| <div class="container">
    4|   <div class="row row-cols-1 row-cols-md-2 g-4">
 >> 5|     <div class="col"><h1>Week <%=foundAnswer.week%> :</h1></div>
    6|     <div class="col" style="position: static; bottom: 0%">
    7|       <h1 style="color: red">
    8|         Disclaimer :

Cannot read properties of null (reading 'week')

I tried removing the spaces and all .. and checked my data tree .. evrything is fine … and frontend works fine.

Tags:

2

Answers


  1. 0

    I want from you to add the following line to your code:-

    console.log(foundAnswer);

    if (!err) {
        ** Add it here **
        res.render('nptel_weeksAnswer', {
          foundAnswer: foundAnswer,
        });
      } else {

    Then run your code and give us the result shown in the consle

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  2. 0

    Be careful if you are using the last version of Mongoose since callbacks are no longer accepted for findOne:

    app.get('/nptel/:courseName/:weekNumber', async function (req, res) {
    try {
        const foundAnswer = Nptel.findOne({
            nptel_name: req.params.courseName,
            week: req.params.weekNumber,
        });
        res.render('nptel_weeksAnswer', { foundAnswer });
    } catch (err) {
        res.render('error');
    }
});

    Make sure to check if foundAnswer has actually been found on EJS:

    <% if (foundAnswer) { %>
    <div class="col"><h1>Week <%=foundAnswer.week%> :</h1></div>
    <div class="nptel_answer mb-2">
    <div class="nptelQ"><h4><%=foundAnswer.question_1%></h4></div>
    <div class="nptelA"><h5><%=foundAnswer.answer_1%></h5></div>
    </div>
<% } else { %>
    <div>No answer found</div>
<% } %>
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