Variable in ejs partial not defined, even though it is?-CodePudding

So I'm following this youtube tutorial, and it's gotten to a part where I should display an error message using an ejs partial. followed the tutorial to a T, but i get this error:

ReferenceError: C:\PATH\mongo_db_app\views\layouts\layout.ejs:11
    9| <body>

    10|     <%- include('../partials/header.ejs') %>

 >> 11|     <%- include('../partials/err_msg.ejs') %>

    12|     <%- body %>

    13| </body>

    14| </html>

C:\PATH\mongo_db_app\views\partials\err_msg.ejs:1
 >> 1| <%= errorMessage %>

errorMessage is not defined
    at eval (eval at compile (C:\PATH\mongo_db_app\node_modules\ejs\lib\ejs.js:673:12), <anonymous>:10:26)
    at err_msg (C:\PATH\mongo_db_app\node_modules\ejs\lib\ejs.js:703:17)
    at include (C:\PATH\mongo_db_app\node_modules\ejs\lib\ejs.js:701:39)
    at eval (eval at compile (C:\PATH\mongo_db_app\node_modules\ejs\lib\ejs.js:673:12), <anonymous>:15:17)
    at layout (C:\PATH\mongo_db_app\node_modules\ejs\lib\ejs.js:703:17)
    at tryHandleCache (C:\PATH\mongo_db_app\node_modules\ejs\lib\ejs.js:274:36)
    at exports.renderFile [as engine] (C:\PATH\mongo_db_app\node_modules\ejs\lib\ejs.js:491:10)
    at View.render (C:\PATH\mongo_db_app\node_modules\express\lib\view.js:135:8)
    at tryRender (C:\PATH\mongo_db_app\node_modules\express\lib\application.js:657:10)
    at Function.render (C:\PATH\mongo_db_app\node_modules\express\lib\application.js:609:3)

The err_msg.ejs contains one line, namely <%= errorMessage %>. The layout file in which it is used is:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Mybrary</title>
</head>
<body>
    <%- include('../partials/header.ejs') %>
    <%- include('../partials/err_msg.ejs') %>
    <%- body %>
</body>
</html>

And this is the code block where errorMessage is coming from:

router.post('/', (req,res) => {
    const author = new Author({
        name: req.body.name
    })
    author.save((err, newAuthor) => {
        if (err){
            res.render('authors/new', {
                author: author,
                errorMessage: 'Error creating author'
            })
        } else {
            //res.redirect(`authors/${newAuthor.id}`)
            res.redirect(`authors`)
        }
    })
})

For more info, here is the github repo: https://github.com/DragosSaviour/Mybrary

Can someone help me understand/solve this problem?

EDIT: I have tried doing

<%if (errorMessage) { %>
    <%= errorMessage %>
<% } %>

the result remains the same.

CodePudding user response：

You need to check if errorMessage exits, if it's not undefined with typeof (your attempt checks if it's truthy, which is why it fails, because it doesn't exist).

Try this:

<%if (typeof errorMessage != "undefined") { %>
    <%= errorMessage %>
<% } %>