Accessing Documents in MongoDB Subdocument

Question

**EDIT: Wow my mistake. I forgot to subtract (-1) from the array.length to get the last item in the array. Rookie mistake!

I'm using an Express server to save data to my MongoDB database. I have one route set up that accepts an object with the following information:

{ handle: "twitterHandle" }

That information is saved based on my schema, here:

const TwitterSchema = new mongoose.Schema({
        handle: {
            type: String,
            required: true
        }
});

Which is stored inside of my user schema, here:

const UserSchema = new mongoose.Schema({
    email: {
        type: String,
        required: true,
        trim: true,
        minLength: 1,
        unique: true,
        validate: {
            validator: (value) => {
                return validator.isEmail(value);
            },
            message: '{VALUE} is not a valid email'
        }
    }
    trackers: {
        tweets: {
            type: [TwitterSchema], // SUBDOCUMENT IS LOCATED HERE
            default: null
        },
        legislation: {
            type: [LegislationSchema],
            default: null
        },
        court_cases: {
            type: [CourtCaseSchema],
            default: null
        }
    }
});

After saving the tweet via a PUSH request to a route on my server, I would like to return the newly saved tweet data, which would be a JSON object with the tweet handle and the _id property, which is generated by MongoDB.

However, I'm not able to access the last item in the tweets subdocument. How do I do that?

Here's the route, /api/users/me/trackers/tweets that handles POST requests to my backend for twitter data:

const post_tweet = (req,res) => {
    User.findOne({_id: "5b7ef883c69aac4cf99acb89"}) // hard coded ID value for now...
        .then((user) => {
            user.trackers.tweets.push(req.body);
            return user.save();
        })
        .then((user) => {
            res.status(200)
                .send(user.trackers.tweets[SOMEHOW GET LAST TWEET?])
        })
        .catch((e) => {
            console.log("Request failed.")
            res.status(400).send(e);
            });
}