I have read through the documentation for connections and am confused about what will occur if I call mongoose.connect on every request to my express server with the same URL and options. Will the previous connection automatically be re-used if one exists or will a new one always be established?

I have disabled buffering as I am running on Vercels Serverless environment and need the retry loop as Vercel sometimes fails to connect to all 3 nodes In my cluster.

Here is my connection code, I call this with await at the start of every request my Express server handles.

const connectDatabase = async function (retries = 5) {
    while (retries) {
        try {
            conn = await mongoose.connect(process.env.DB_URL, {
                useNewUrlParser: true,
                useUnifiedTopology: true,
                family: 4,
                bufferCommands: false,
            });
            return conn;
        } catch (err) {
            console.warn(err);
            retries -= 1;
            console.warn(`Retries left: ${retries}`);
            // wait 1 second
            await new Promise(res => setTimeout(res, 1000));
        }
    }

    // If we're here, we failed to connect after 5 attempts
    throw new Error('Failed to connect to DB');
};