NodeJS中Post不是构造函数及表单提交验证错误求助

Let's break down and resolve both of the problems you're facing with your form submission flow:

1. Fixing TypeError: Post is not a Constructor #

The root cause here is how you're importing the Post model. In your Post.js, you're exporting the Mongoose model directly:

module.exports = mongoose.model('Post', PostSchema);

But in Controller.js, you're trying to access a Post property from the imported module, which doesn't exist.

Update your Controller.js import line to:

const Post = require('../models/postModel'); // No .Post needed

2. Fixing ValidationError & Unresponsive Page #

This issue has a few interconnected causes—let's address each one:

a. Ensure Form Data is Parsed #

Express doesn't automatically parse form-encoded data by default. If you haven't already, add this middleware to your main Express app file (e.g., app.js):

// Parse URL-encoded bodies (form data)
app.use(express.urlencoded({ extended: true }));

Without this, req.body will be empty, which triggers the validation error because all required fields are missing.

b. Correct Flash Message Usage #

You're calling flash() directly, but flash messages are attached to the req object via express-session. Replace your flash call with:

req.flash('success-message', 'Yay its fine');

c. Handle Promise Rejections #

Your newPost.save() only has a .then() block, but no .catch() to handle validation errors or database issues. This is why your page hangs—when the promise rejects, there's no code to send a response back to the client.

Update your submitPosts function to include error handling:

submitPosts: (req, res) => {
  const newPost = new Post({
    surname: req.body.surname,
    name: req.body.name,
    biography: req.body.biography,
    profilpicture: req.body.profilpicture
  });

  newPost.save()
    .then(post => {
      console.log(post);
      req.flash('success-message', 'Yay its fine');
      res.redirect('/admin');
    })
    .catch(err => {
      // Catch validation errors and flash them
      req.flash('error-message', err.message);
      // Redirect back to the form page so the user can fix issues
      res.redirect('/your-form-page-url'); // Replace with your actual form route
    });
}

d. Double-Check Form Field Names #

Even though you mentioned setting the name attributes, double-verify that each input's name exactly matches the fields in your schema (surname, name, biography, profilpicture). A typo here would also cause empty values and validation errors.

内容的提问来源于stack exchange，提问作者Dariun