Saving an array (of 'tags') to MongoDB using Mongoose

Question

I'm playing around with Mongoose and I'm having trouble saving to an array. For example, I have an input field on a page for comma-separated tags . I grab these from req.body.tags, remove the white space, and split them by the commas to get an array of the tags. Now, how do I save this array back to my database? I'm guessing I've set up this part of the schema wrong but I'm not sure what's right, to be honest. The schema I have so far is:

var postSchema = mongoose.Schema({
  title: String,
  permalink: String,
  content: String,
  author: {
    id: String,
    name: String,
  },
  postDate: {
    type: Date,
    default: Date.now
  },
});

If I was to save tags (from a post, for example) would it be best to have an array called tags and then each tag has a name (and id?)? If so, would I just add something like this (below) to the schema? The idea of adding tags to a post is so that I can display them (as links) on the post and be able to search the database for all posts with a certain tag. Is this the right way to go about it?

tags: [{
  name: String,
  id: String
}]

When posting to the new post route, I'm doing the following:

  post = new Post(req.body);
  tags = req.body.tags.replace(/\s/g,'').split(',');
  // maybe post.tags = tags ?    
  post.save(function(err) {
    if (!err) {
      res.redirect('/posts');
    } else {
      ...
    }
  });

This successfully saves all other fields submitted (title, author, content, etc.) but I'm not sure how I can save the newly-created tags back to the database. Any advice here would be very welcome as I'm new to this and keen to keep learning. Thanks!

Answer 1

If you really want your "tags" array to have a name field and a generated _id field then define another schema and embed it:

var tagSchema = mongoose.Schema({
    name: String
});

var postSchema = mongoose.Schema({
  title: String,
  permalink: String,
  content: String,
  author: {
    id: String,
    name: String,
  },
  postDate: {
    type: Date,
    default: Date.now
  },
  tags: [tagSchema]
});

Then manipulate the input to the correct structure before you create the Post object:

req.body.tags = req.body.tags.replace(/\s/''/g).split(",").map(function(tag) {
    return { "name": tag };
});

var post = new Post(req.body);

Or just leave it as an array of plain strings:

var postSchema = mongoose.Schema({
  title: String,
  permalink: String,
  content: String,
  author: {
    id: String,
    name: String,
  },
  postDate: {
    type: Date,
    default: Date.now
  },
  tags: [String]
});

And don't worry about mapping the object property:

req.body.tags = req.body.tags.replace(/\s/''/g).split(",");
var post = new Post(req.body);