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I want to pass a list of objects from my database to the pug view, but I got the Error at the bottom of the post. Here is the code of what I try:

app.js Here is the function to get the objects and put them into a list. Thers also the route with the function call to get the list.

//...
function getEntryList(db)  {
    connection.query(connection.format('SELECT name FROM ??', [db]), (err, result, fields) => {
        if (err || !result) {
            utils.log(`[MySQL] ${err}`);
            return Array();
        }

        list = Array();
        Object.keys(result).forEach(key => {
            row = result[key];
            entry = {title: row.name, url: `/${db}/${row.id}`};
            list.push(entry);
        });
        return list;
    });
}
//...
app.get('/employees', localSession, (req, res) => {
    list = getEntryList('employees');
    res.render('employees', {title: 'Employees', list: list});
});
//...

content_with_list.pug This view is where the error happens.

extends layout 

block content
    .content-info
        block content_info
    .content-list.navigation 
        nav 
            ul 
                each entry in list
                    li 
                        a(href=entry.url)= entry.title
                else 
                    li No employees found!

employees.pug This view extends from the view with the error.

extends content_with_list 

block content_info
    if result
        table
            tr
                td(rowspan='7' style='vertical-align: top;')
                    div
                        img(src="#{result.image}")
                        p Level 
                            span(style={color: secLevel.color})= secLevel.secName
                    
                td Name:
                td
            tr
                td MC-Username:
                td
            tr
                td Address:
                td
            tr
                td Nationality:
                td
            tr
                td Species:
                td
            tr
                td Gender:
                td
            tr
                td Job:
                td
            tr
                td
                td Projects:
                td

I get this error:

TypeError: project\views\content_with_list.pug:9
    7|         nav 

    8|             ul 

  > 9|                 each entry in list

    10|                     li 

    11|                         a(href=entry.url)= entry.title

    12|                 else 


Cannot read property 'length' of undefined
    at eval (eval at wrap (project\node_modules\pug-runtime\wrap.js:6:10), <anonymous>:163:32)
    at eval (eval at wrap (project\node_modules\pug-runtime\wrap.js:6:10), <anonymous>:203:4)
    at template (eval at wrap (project\node_modules\pug-runtime\wrap.js:6:10), <anonymous>:295:7)
    at Object.exports.renderFile (project\node_modules\pug\lib\index.js:454:38)
    at Object.exports.renderFile (project\node_modules\pug\lib\index.js:444:21)
    at View.exports.__express [as engine] (project\node_modules\pug\lib\index.js:493:11)
    at View.render (project\node_modules\express\lib\view.js:135:8)
    at tryRender (project\node_modules\express\lib\application.js:640:10)
    at Function.render (project\node_modules\express\lib\application.js:592:3)
    at ServerResponse.render (project\node_modules\express\lib\response.js:1012:7)
KnusperflockeOfDeath
  • 11
  • 2
  • `getEntryList()` is returning `undefined`. Consider passing it a callback to grab your data or use a Promise based approached – Nick Parsons Aug 07 '21 at 14:14
  • ```app.get('/employees', localSession, (req, res) => { new Promise((resolve, reject) => {resolve(getEntryList('employees'))}).then((list) => res.render('employees', {title: 'Employees', list: list})); }); ``` and ```app.get('/employees', localSession, (req, res) => { new Promise((resolve, reject) => { list = getEntryList('employees'); resolve(list); }).then((list) => res.render('employees', {title: 'Employees', list: list})); }); ``` I tried this but its throw the same error. – KnusperflockeOfDeath Aug 07 '21 at 14:48
  • I suggest reading up on Promises, definitely useful to know if you're using node.js. You don't wrap the call to `getEntryList()` in a Promise, but instead wrap your asynchronous code (ie: the database query which takes time to execute) in a Promise, eg: https://jsfiddle.net/3z65j1vn/1 – Nick Parsons Aug 07 '21 at 14:53
  • 1
    Uwu, thank you so much. it works. I thought that the promise has to wrap my whole function, but the promise has to be the async proccese returned by my fuction. sry for bad english^^ – KnusperflockeOfDeath Aug 07 '21 at 15:01

0 Answers0