Implement follow/unfollow like action using Node + Express.js and MongoDB - node.js

Question

I'm trying to design a Twitter style API. I've come up with the following Schema:
User collection
username
password
Followers collection
follower_id
followee_id
start_date
end_date
Eg:
{
follower_id: 1235
followee_id: 1024
start_date: November 3, 2018
}
which means user 1024 follows user 1235.
Absence of end_date indicates that the user is still following.
Tweets collection
text
date_created
user_id
user_id will be a reference to User collection.
How can I achieve follow/unfollow action with above schema?

Answer 1

For the user collection, you could have a following[] array. As in, you put each user id that they are following in the array and then remove it when they unfollow a person. Then with express, you can handle a post request sent by the front end with express. Of course you would need a boolean to say like:
// To show the button saying "follow" or "unfollow"
var followingArray = [123414, 312456, 656465];
var following = false;
if (followingArray.indexOf(userid)) {
following = true;
} else {
following = false;
}
Obviously, this is just a concept and you would need other code from mongoose or the regular mongodb module to get the user id. This would also decide whether or not the post request link is going to be http://myapp.com/follow or http://myapp.com/unfollow. Based on these two post requests, you would handle the data like the user id with body-parser and express:
var bodyParser = require('body-parser');
const express = require('express');
const app = express();
const port = 8080
app.use( bodyParser.json() ); // to support JSON-encoded bodies
app.use(bodyParser.urlencoded({ // to support URL-encoded bodies
extended: true
}));
app.post('/follow', (req, res) => {
//handle data here for a request to follow someone
var userid = req.body.userid;
})
app.post('/unfollow', (req, res) => {
//handle data here for a request to unfollow someone
var userid = req.body.userid
})
app.listen(port, () => {
console.log(`Server running on ${port}`);
})
Then you would use this data with mongoose or the mongodb module to remove or add that user id from the array and change the following boolean to true or false. Then if you wanted to add other features like a followers list or a following list, you could use the user id to do so. I am not giving exact code on how to do this as there are many concepts involved. I am just trying to give you the concepts that you would use in doing so.

Answer 2

I recommend this:
Keep the database as "flat" as possible. That means fewer collections.
You'd probably need only 2 collections: users and tweets
In your users schema should look something like this:
// Asuming you use mongoose, if you haven't heard about it, you should look it up.
const userSchema = new Schema({
username: {type: String, required: true, trim: true},
password: {type: String, required: true},
following: {type: Array}, // Store all user id of the people that this user is following in an array.
followers: {type: Array}, // Store all users id of this user's followers in an array.
tweets: {
type: Schema.Types.ObjectId, // Store all tweets by this user in an object.
ref: "Tweet" // Link to Tweet Schema
}
}, {_id: true});
Your tweets schema:
const tweetSchema = new Schema({
text: {type: String, required: true}
// You can also have a userId to store the id of the user whose this tweet belongs to
}, {_id: true});
You then can use create to create users or tweets, update to edit following or followers.
Obviously there are several ways to achieve what you want. This is just one of them.

Answer 3

Following Solution Works for me:
const mongoose = require("mongoose");
const userSchema = new mongoose.Schema(
{
name: {
type: String,
trim: true,
},
following: {
type: Array
},
followers: {
type: Array
},
},
{
timestamps: true,
}
);
const User = mongoose.model("User", userSchema);
module.exports = User;
router.patch("/api/v1/follow/", auth, async (req, res) => {
try {
let whomFollowed = await User.findByIdAndUpdate({ _id: req.body.followingId},
{ $push: { following: req.body.followerId } }
);
let whoFollowedMe = await User.findByIdAndUpdate({ _id: req.body.followerId },
{ $push: { followers: req.body.followingId } }
)
return res.status(200).send({ message: "User Follow Success"});
} catch (e) {
return res.status(500).send({ message: "User Follow Failed", data: e.message });
}
});
router.patch("/api/v1/unfollow/", auth, async (req, res) => {
try {
let whomUnFollowed = await User.findByIdAndUpdate({ _id: req.body.followingId },
{ $pull: { following: req.body.followerId } }
);
let whoUnFollowedMe = await User.findByIdAndUpdate({ _id: req.body.followerId },
{ $pull: { followers: req.body.followingId } }
)
return res.status(200).send({ message: "User UnFollow Success"});
} catch (e) {
return res.status(500).send({ message: "User UnFollow Failed", data: e.message });
}
});