Poolerz

1. DBSCAN Clustering for Carpool Matching

Implemented DBSCAN (Density-Based Spatial Clustering) to automatically group people by geographic proximity. Unlike k-means, DBSCAN doesn't require knowing the number of carpools in advance.

import { DBSCAN } from 'density-clustering'

function createCarpools(users: User[], maxDistance: number) {
  // Extract coordinates: [latitude, longitude]
  const coordinates = users.map(u => [u.location.lat, u.location.lng])

  // DBSCAN: eps = max distance (km), minPts = 2
  const dbscan = new DBSCAN()
  const clusters = dbscan.run(coordinates, maxDistance, 2)

  // Map clusters to carpools
  return clusters.map(clusterIndices => ({
    members: clusterIndices.map(i => users[i]),
    centroid: calculateCentroid(clusterIndices, coordinates)
  }))
}

2. Google OAuth Authentication

Integrated Google OAuth to verify university email addresses and prevent spam. Used NextAuth.js for session management.

// pages/api/auth/[...nextauth].ts
import NextAuth from 'next-auth'
import GoogleProvider from 'next-auth/providers/google'

export default NextAuth({
  providers: [
    GoogleProvider({
      clientId: process.env.GOOGLE_CLIENT_ID,
      clientSecret: process.env.GOOGLE_CLIENT_SECRET,
    })
  ],
  callbacks: {
    async signIn({ profile }) {
      // Only allow university emails
      return profile.email?.endsWith('@gatech.edu') ?? false
    }
  }
})

3. Real-Time Roster Updates

Implemented SWR (stale-while-revalidate) for optimistic UI updates. When a user joins/leaves a carpool, the UI updates immediately while revalidating in the background.

import useSWR from 'swr'

function CarpoolRoster({ carpoolId }: { carpoolId: string }) {
  const { data, mutate } = useSWR(`/api/carpools/${carpoolId}`)

  const joinCarpool = async () => {
    // Optimistic update
    mutate({ ...data, members: [...data.members, currentUser] }, false)

    // Actual API call
    await fetch(`/api/carpools/${carpoolId}/join`, { method: 'POST' })

    // Revalidate
    mutate()
  }

  return <div>{/* Roster UI */}</div>
}

4. Multi-Step Registration Flow

Built a clean onboarding flow with form validation, location input (geocoding via Google Maps API), and availability selection.

5. Vercel Serverless Deployment

Deployed on Vercel with serverless functions for API routes and MongoDB Atlas for data storage. Zero-cost deployment for student project.