Import protection still running on client bundle (?)

import '@tanstack/react-start/server-only';
import * as mongoose from 'mongoose';

console.log(process.env);
const url = process.env.MONGODB_URL;
const dbUsername = process.env.MONGODB_USERNAME;
const dbPassword = process.env.MONGODB_PASSWORD;
if (!url) {
    throw new Error(`MONGODB_URL environment variable is not set`);
}

if (!dbUsername) {
    throw new Error(`MONGODB_USERNAME environment variable is not set`);
}

if (!dbPassword) {
    throw new Error(`MONGODB_PASSWORD environment variable is not set`);
}

export const connectToDatabase = async () => {
    try {
        const db = await mongoose.connect(url, {
            auth: {
                username: dbUsername,
                password: dbPassword,
            },
            authSource: 'admin',
        });
        console.log('Connected to MongoDB');
        return db;
    } catch (error) {
        console.error('Error connecting to MongoDB:', error);
        throw error;
    }
};