refactor(github): extract developer score into pure helper

Author: saagnik23

lib/github.test.ts

@@ -16,6 +16,7 @@ import {
   fetchOrgMembers,
   getOrgDashboardData,
   getWrappedData,
+  computeDeveloperScore,
 } from './github';
 import type { ContributionCalendar } from '../types';
 
@@ -1305,3 +1306,96 @@ describe('getWrappedData', () => {
     expect(body.variables.to).toBe('2024-12-31T23:59:59Z');
   });
 });
+
+describe('computeDeveloperScore', () => {
+  it('handles all-zero inputs', () => {
+    const score = computeDeveloperScore({
+      repos: 0,
+      followers: 0,
+      stars: 0,
+      contributions: 0,
+      longestStreak: 0,
+    });
+    expect(score).toBe(0);
+  });
+
+  it('calculates perfect 100 for exact saturation threshold values', () => {
+    const score = computeDeveloperScore({
+      repos: 50,
+      followers: 50,
+      stars: 100,
+      contributions: 400,
+      longestStreak: 50,
+    });
+    expect(score).toBe(100);
+  });
+
+  it('clamps the developer score to a maximum of 100 under excess inputs', () => {
+    const score = computeDeveloperScore({
+      repos: 1000,
+      followers: 500,
+      stars: 9999,
+      contributions: 10000,
+      longestStreak: 365,
+    });
+    expect(score).toBe(100);
+  });
+
+  it('correctly calculates developer score under realistic normal values with rounding', () => {
+    const score = computeDeveloperScore({
+      repos: 10, // 10 * 0.5 = 5 pts
+      followers: 8, // 8 * 0.5 = 4 pts
+      stars: 15, // 15 * 0.2 = 3 pts
+      contributions: 120, // 120 / 20 = 6 pts
+      longestStreak: 12, // 12 * 0.2 = 2.4 pts
+    }); // Total = 20.4 -> rounded to 20
+    expect(score).toBe(20);
+  });
+
+  it('handles individual factor saturation caps correctly', () => {
+    // repos saturates at 50 (25 pts), followers saturates at 50 (25 pts)
+    const score = computeDeveloperScore({
+      repos: 100, // Caps at 25 pts
+      followers: 60, // Caps at 25 pts
+      stars: 0,
+      contributions: 0,
+      longestStreak: 0,
+    });
+    expect(score).toBe(50);
+  });
+
+  it('handles small fractional values and rounds to nearest integer correctly', () => {
+    // longestStreak of 3 yields 3 * 0.2 = 0.6 -> rounds to 1
+    expect(
+      computeDeveloperScore({
+        repos: 0,
+        followers: 0,
+        stars: 0,
+        contributions: 0,
+        longestStreak: 3,
+      })
+    ).toBe(1);
+
+    // sum of small fractional parts: 1 repos (0.5) + 1 followers (0.5) + 1 stars (0.2) + 1 contributions (0.05) + 1 longestStreak (0.2) = 1.45 -> rounds to 1
+    expect(
+      computeDeveloperScore({
+        repos: 1,
+        followers: 1,
+        stars: 1,
+        contributions: 1,
+        longestStreak: 1,
+      })
+    ).toBe(1);
+
+    // sum: 1 repos (0.5) + 1 followers (0.5) + 1 stars (0.2) + 1 contributions (0.05) + 2 longestStreak (0.4) = 1.65 -> rounds to 2
+    expect(
+      computeDeveloperScore({
+        repos: 1,
+        followers: 1,
+        stars: 1,
+        contributions: 1,
+        longestStreak: 2,
+      })
+    ).toBe(2);
+  });
+});

lib/github.ts

@@ -728,6 +728,33 @@ export function buildCommitClock(allDays: ContributionDay[]) {
   return dayNames.map((name, i) => ({ day: name, commits: dayTotals[i] }));
 }
 
+export interface DeveloperScoreInput {
+  repos: number;
+  followers: number;
+  stars: number;
+  contributions: number;
+  longestStreak: number;
+}
+
+export function computeDeveloperScore({
+  repos,
+  followers,
+  stars,
+  contributions,
+  longestStreak,
+}: DeveloperScoreInput): number {
+  return Math.min(
+    Math.round(
+      Math.min(repos * 0.5, 25) +
+        Math.min(followers * 0.5, 25) +
+        Math.min(stars * 0.2, 20) +
+        Math.min(contributions / 20, 20) +
+        Math.min(longestStreak * 0.2, 10)
+    ),
+    100
+  );
+}
+
 export async function getFullDashboardData(username: string, options: FetchOptions = {}) {
   const [profileResult, reposResult, calendarResult] = await Promise.allSettled([
     fetchUserProfile(username, options),
@@ -751,16 +778,19 @@ export async function getFullDashboardData(username: string, options: FetchOptio
   const streakStats = calculateStreak(calendarData);
   const totalStars = reposData.reduce((acc, repo) => acc + repo.stargazers_count, 0);
 
-  const developerScore = Math.min(
-    Math.round(
-      Math.min(profileData.public_repos * 0.5, 25) +
-        Math.min(profileData.followers * 0.5, 25) +
-        Math.min(totalStars * 0.2, 20) +
-        Math.min(streakStats.totalContributions / 20, 20) +
-        Math.min(streakStats.longestStreak * 0.2, 10)
-    ),
-    100
-  );
+  // Developer Score — 5-factor weighted formula (max 100 pts)
+  // Repos:         up to 25 pts  (saturates at 50 public repos)
+  // Followers:     up to 25 pts  (saturates at 50 followers)
+  // Stars:         up to 20 pts  (saturates at 100 total stars)
+  // Contributions: up to 20 pts  (saturates at 400 yearly contributions)
+  // Streak:        up to 10 pts  (saturates at a 50-day longest streak)
+  const developerScore = computeDeveloperScore({
+    repos: profileData.public_repos,
+    followers: profileData.followers,
+    stars: totalStars,
+    contributions: streakStats.totalContributions,
+    longestStreak: streakStats.longestStreak,
+  });
 
   const profile = {
     username: profileData.login,