Cannot read property 'substring' of undefined in ejs

Question

When I try to add new blog posts to my website I am continuously getting this error:

TypeError: C:\Users\shruti\Desktop\ejs-challenge\views\home.ejs:15 13|
14|       <p>

15|         <%= post.content.substr(0, 100) %>

16|         <a href="/posts/<%=post._id%>">Read More</a>

17|       </p>

18|       <% })%>
Cannot read property 'substr' of undefined at eval (eval at compile (C:\Users\shruti\Desktop\ejs-challenge\node_modules\ejs\lib\ejs.js:618:12), :22:39) at Array.forEach () at eval (eval at compile (C:\Users\shruti\Desktop\ejs-challenge\node_modules\ejs\lib\ejs.js:618:12), :16:14) at returnedFn (C:\Users\shruti\Desktop\ejs-challenge\node_modules\ejs\lib\ejs.js:653:17) at tryHandleCache (C:\Users\shruti\Desktop\ejs-challenge\node_modules\ejs\lib\ejs.js:251:36) at View.exports.renderFile [as engine] (C:\Users\shruti\Desktop\ejs-challenge\node_modules\ejs\lib\ejs.js:482:10) at View.render (C:\Users\shruti\Desktop\ejs-challenge\node_modules\express\lib\view.js:135:8) at tryRender (C:\Users\shruti\Desktop\ejs-challenge\node_modules\express\lib\application.js:640:10) at Function.render (C:\Users\shruti\Desktop\ejs-challenge\node_modules\express\lib\application.js:592:3) at ServerResponse.render (C:\Users\shruti\Desktop\ejs-challenge\node_modules\express\lib\response.js:1008:7) at C:\Users\shruti\Desktop\ejs-challenge\app.js:35:9 at C:\Users\shruti\Desktop\ejs-challenge\node_modules\mongoose\lib\model.js:4846:16 at C:\Users\shruti\Desktop\ejs-challenge\node_modules\mongoose\lib\model.js:4846:16 at C:\Users\shruti\Desktop\ejs-challenge\node_modules\mongoose\lib\helpers\promiseOrCallback.js:24:16 at C:\Users\shruti\Desktop\ejs-challenge\node_modules\mongoose\lib\model.js:4869:21 at C:\Users\shruti\Desktop\ejs-challenge\node_modules\mongoose\lib\query.js:4397:11

home.ejs:

<%- include("partials/header") -%>

    <h1>HOME</h1>
    <p> <%= startingContent %> </p>

    <% console.log(posts); %>

    <div class="">
      <% posts.forEach(function(post){ %>
      <h1><%= post.title%></h1>

      <p>
        <%= post.content.substr(0, 100) %>
        <a href="/posts/<%=post._id%>">Read More</a>
      </p>
      <% })%>


        <form  action="/compose">
           <button class="btn btn-primary" type="compose" name="button">COMPOSE</button>
        </form>

    </div>


    <%- include("partials/footer") -%>

Does this answer your question? How to set character limits in content in ejs template — dawsnap
– dawsnap, Commented Nov 30, 2020 at 9:20

Zsolt Meszaros · Accepted Answer · 2020-11-30 12:01:28Z

1

The error message says that it "Cannot read property 'substr' of undefined", which means post.content is undefined inside your posts.forEach() loop. Try to log post and check its content.

answered Nov 30, 2020 at 12:01

Zsolt Meszaros

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Comments

Kumar Shanu · Accepted Answer · 2022-04-22 11:26:02Z

0

I went through your problem and the easiest solution to that is put brackets between post.content and frame it this way:

<%= (post.content).substr(0, 100) %>

It is working i tried it myself, Enjoy learning

answered Apr 22, 2022 at 11:26

Kumar Shanu

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1 Comment

Community Over a year ago

Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center.

Piotr Krajewski · Accepted Answer · 2022-07-07 11:57:04Z

0

Probably there are empty post.content values in your database and when the forEach loop retrieves them the function Cannot read property of 'Undefined' meaning empty value. Search through your DB to locate this null/ empty content fields and update or remove them.

answered Jul 7, 2022 at 11:57

Piotr Krajewski

1

1 Comment

Community Over a year ago

Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center.

Glenn R. Tomassi · Accepted Answer · 2022-09-07 16:26:39Z

0

To solve this issue you must drop your MongoDB BlogDB table. This issue happens because you have a non-defined variable (post.content) on the very first row/register.

first empty row

answered Sep 7, 2022 at 16:26

Glenn R. Tomassi

11 bronze badge

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