这是使用node.js和jade在目录中列出文件的方法

Question

I am trying to list a file in a directory using jade and node.js but I am not sure if below is the right way of doing it, as I receive a type error that says

Cannot read property 'length' of undefined

Any hint would be much appreciated

h1 Your tasks
p


// list all the file
ul
  for file in files
    li
      p= file

node.js code

app.get('/tasks', function(req, res){


  fs.readdir('tasks/index', function(err, data){
    res.render('tasks/index', {"files": data});
  });

});

update

app.get('/tasks', function(req, res){


  fs.readdir('tasks', function(err, data){
    res.render('tasks/index', {"files": data});
  });

});

error

500 TypeError: /path/views/tasks/index.jade:7 5| // list all the file 6| ul > 7| each file in files 8| li 9| p= file 10| Cannot read property 'length' of undefined

    5| // list all the file
    6| ul
    > 7| each file in files
    8| li
    9| p= file
    10|
    Cannot read property 'length' of undefined

Answer 1

OK, several issues:

1. You need to use each file in files instead of for
2. 'tasks/index' is being treated as both a directory and a file. It can't be both, and it's probably a file, so your readDir call is probably throwing an error which is why data (and thus files ) is undefined.
3. fs.readDir is going to treat relative paths as relative to process.cwd whereas res.render treats relative paths relative to express's 'views' setting.
4. Ignoring the error thrown by step 3 is just making your life harder, which is why it's a bad habit.

---

fs.readdir(__dirname + '/views/tasks', function(error, data){
  if (error) {
      res.status(500).send(error);
      return;
  }
  res.render('tasks/index', {"files": data});
});

I don't know your filesystem organization entirely, so the paths are just guesses, but the root of your problem seems to be not coding properly in terms of filesystem organization.