Switch to data-driven percentiles

src/calculateRank.js

@@ -1,12 +1,91 @@
-function exponential_cdf(x) {
-  return 1 - 2 ** -x;
-}
+function score(x, quantiles) {
+  const i = quantiles.findIndex((q) => x < q);
+
+  if (i == 0) {
+    return 0.0;
+  } else if (i == -1) {
+    return 1.0;
+  }
 
-function log_normal_cdf(x) {
-  // approximation
-  return x / (1 + x);
+  const a = quantiles[i - 1];
+  const b = quantiles[i];
+
+  return ((x - a) / (b - a) + i - 1) / (quantiles.length - 1);
 }
 
+const QUANTILES = {
+  commits: [
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 3, 3,
+    4, 4, 5, 6, 7, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17, 19, 20, 22, 23, 25, 27,
+    29, 31, 33, 35, 38, 40, 43, 45, 48, 51, 54, 57, 60, 64, 67, 71, 76, 80, 85,
+    89, 94, 99, 105, 111, 118, 125, 132, 140, 147, 155, 164, 173, 184, 195, 207,
+    220, 233, 249, 265, 284, 304, 326, 353, 380, 411, 451, 495, 545, 611, 691,
+    794, 933, 1195, 1704, 9722,
+  ],
+  all_commits: [
+    0, 0, 0, 0, 2, 4, 8, 11, 15, 19, 23, 27, 32, 36, 41, 45, 50, 55, 60, 65, 71,
+    76, 82, 87, 93, 99, 105, 111, 117, 124, 131, 137, 145, 151, 159, 166, 174,
+    182, 190, 198, 207, 215, 225, 234, 244, 253, 264, 274, 285, 296, 306, 318,
+    330, 342, 355, 368, 382, 396, 409, 424, 440, 457, 475, 493, 512, 531, 551,
+    570, 593, 618, 643, 667, 695, 723, 752, 784, 815, 857, 893, 934, 984, 1037,
+    1094, 1152, 1217, 1289, 1379, 1475, 1576, 1696, 1851, 2023, 2232, 2480,
+    2835, 3242, 3885, 4868, 6614, 11801, 792319,
+  ],
+  prs: [
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1,
+    1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 7,
+    8, 8, 9, 10, 10, 11, 11, 12, 13, 14, 14, 15, 16, 17, 18, 19, 20, 21, 23, 24,
+    25, 27, 28, 30, 32, 34, 36, 38, 40, 43, 46, 50, 53, 57, 61, 65, 70, 76, 83,
+    90, 99, 110, 123, 139, 159, 185, 219, 273, 360, 562, 2291,
+  ],
+  issues: [
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3,
+    4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 7, 8, 8, 9, 10, 10, 11, 12, 12, 13, 14, 15,
+    16, 17, 19, 20, 21, 23, 24, 26, 28, 30, 32, 35, 38, 41, 45, 49, 54, 59, 66,
+    73, 82, 92, 106, 123, 150, 186, 255, 409, 1590,
+  ],
+  reviews: [
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 2, 2, 3, 4, 5, 6, 8, 11, 15, 23, 36, 61,
+    129, 764,
+  ],
+  repos: [
+    0, 0, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 6, 7, 7, 8, 8, 8, 9, 9, 10, 10, 11,
+    11, 12, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 19, 20,
+    20, 21, 21, 22, 22, 23, 24, 24, 25, 25, 26, 27, 28, 28, 29, 30, 30, 31, 32,
+    33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 45, 46, 47, 49, 50, 52, 54, 56,
+    58, 60, 62, 65, 68, 70, 74, 77, 82, 86, 92, 98, 105, 115, 127, 144, 170,
+    211, 316, 2002,
+  ],
+  stars: [
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1,
+    1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 6, 6,
+    7, 7, 8, 8, 9, 9, 10, 11, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 24,
+    26, 28, 30, 31, 33, 35, 38, 41, 44, 48, 52, 56, 61, 67, 74, 83, 93, 104,
+    117, 134, 154, 181, 215, 257, 321, 417, 565, 818, 1298, 2599, 18304,
+  ],
+  followers: [
+    0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4,
+    5, 5, 5, 5, 6, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 10, 11, 11, 12, 12,
+    13, 13, 14, 14, 15, 15, 16, 16, 17, 18, 18, 19, 20, 20, 21, 22, 23, 24, 25,
+    26, 27, 28, 29, 30, 32, 33, 35, 36, 38, 40, 42, 44, 46, 49, 51, 54, 57, 61,
+    65, 70, 75, 81, 88, 97, 108, 121, 139, 161, 193, 240, 334, 569, 3583,
+  ],
+};
+
+const WEIGHT = {
+  commits: 2.0,
+  prs: 3.0,
+  issues: 1.0,
+  reviews: 0.5,
+  repos: 0.0,
+  stars: 4.0,
+  followers: 1.0,
+};
+
 /**
  * Calculates the users rank.
  *
@@ -27,48 +106,36 @@ function calculateRank({
   prs,
   issues,
   reviews,
-  // eslint-disable-next-line no-unused-vars
-  repos, // unused
+  repos,
   stars,
   followers,
 }) {
-  const COMMITS_MEDIAN = all_commits ? 1000 : 250,
-    COMMITS_WEIGHT = 2;
-  const PRS_MEDIAN = 50,
-    PRS_WEIGHT = 3;
-  const ISSUES_MEDIAN = 25,
-    ISSUES_WEIGHT = 1;
-  const REVIEWS_MEDIAN = 2,
-    REVIEWS_WEIGHT = 1;
-  const STARS_MEDIAN = 50,
-    STARS_WEIGHT = 4;
-  const FOLLOWERS_MEDIAN = 10,
-    FOLLOWERS_WEIGHT = 1;
-
-  const TOTAL_WEIGHT =
-    COMMITS_WEIGHT +
-    PRS_WEIGHT +
-    ISSUES_WEIGHT +
-    REVIEWS_WEIGHT +
-    STARS_WEIGHT +
-    FOLLOWERS_WEIGHT;
-
   const THRESHOLDS = [1, 12.5, 25, 37.5, 50, 62.5, 75, 87.5, 100];
   const LEVELS = ["S", "A+", "A", "A-", "B+", "B", "B-", "C+", "C"];
 
-  const rank =
-    1 -
-    (COMMITS_WEIGHT * exponential_cdf(commits / COMMITS_MEDIAN) +
-      PRS_WEIGHT * exponential_cdf(prs / PRS_MEDIAN) +
-      ISSUES_WEIGHT * exponential_cdf(issues / ISSUES_MEDIAN) +
-      REVIEWS_WEIGHT * exponential_cdf(reviews / REVIEWS_MEDIAN) +
-      STARS_WEIGHT * log_normal_cdf(stars / STARS_MEDIAN) +
-      FOLLOWERS_WEIGHT * log_normal_cdf(followers / FOLLOWERS_MEDIAN)) /
-      TOTAL_WEIGHT;
+  const total_weight =
+    WEIGHT.commits +
+    WEIGHT.prs +
+    WEIGHT.issues +
+    WEIGHT.reviews +
+    WEIGHT.repos +
+    WEIGHT.stars +
+    WEIGHT.followers;
+
+  const total_score =
+    WEIGHT.commits *
+      score(commits, all_commits ? QUANTILES.all_commits : QUANTILES.commits) +
+    WEIGHT.prs * score(prs, QUANTILES.prs) +
+    WEIGHT.issues * score(issues, QUANTILES.issues) +
+    WEIGHT.reviews * score(reviews, QUANTILES.reviews) +
+    WEIGHT.repos * score(repos, QUANTILES.repos) +
+    WEIGHT.stars * score(stars, QUANTILES.stars) +
+    WEIGHT.followers * score(followers, QUANTILES.followers);
 
-  const level = LEVELS[THRESHOLDS.findIndex((t) => rank * 100 <= t)];
+  const percentile = 100 * (1 - total_score / total_weight);
+  const level = LEVELS[THRESHOLDS.findIndex((t) => percentile <= t)];
 
-  return { level, percentile: rank * 100 };
+  return { level, percentile };
 }
 
 export { calculateRank };

tests/calculateRank.test.js

@@ -3,7 +3,7 @@ import { calculateRank } from "../src/calculateRank.js";
 import { expect, it, describe } from "@jest/globals";
 
 describe("Test calculateRank", () => {
-  it("new user gets C rank", () => {
+  it("new user gets C+ rank", () => {
     expect(
       calculateRank({
         all_commits: false,
@@ -15,82 +15,67 @@ describe("Test calculateRank", () => {
         stars: 0,
         followers: 0,
       }),
-    ).toStrictEqual({ level: "C", percentile: 100 });
+    ).toStrictEqual({ level: "C+", percentile: 78.26086956521738 });
   });
 
-  it("beginner user gets B- rank", () => {
+  it("beginner user gets B rank", () => {
     expect(
       calculateRank({
         all_commits: false,
-        commits: 125,
-        prs: 25,
-        issues: 10,
-        reviews: 5,
-        repos: 0,
-        stars: 25,
+        commits: 50,
+        prs: 5,
+        issues: 5,
+        reviews: 0,
+        repos: 5,
+        stars: 5,
         followers: 5,
       }),
-    ).toStrictEqual({ level: "B-", percentile: 65.02918514848255 });
+    ).toStrictEqual({ level: "B", percentile: 51.97101449275363 });
   });
 
-  it("median user gets B+ rank", () => {
+  it("advanced user gets A- rank", () => {
     expect(
       calculateRank({
         all_commits: false,
         commits: 250,
-        prs: 50,
+        prs: 25,
         issues: 25,
-        reviews: 10,
-        repos: 0,
-        stars: 50,
-        followers: 10,
+        reviews: 0,
+        repos: 25,
+        stars: 25,
+        followers: 25,
       }),
-    ).toStrictEqual({ level: "B+", percentile: 46.09375 });
+    ).toStrictEqual({ level: "A-", percentile: 27.07608695652174 });
   });
 
-  it("average user gets B+ rank (include_all_commits)", () => {
+  it("advanced user gets A- rank (include_all_commits)", () => {
     expect(
       calculateRank({
         all_commits: true,
         commits: 1000,
-        prs: 50,
+        prs: 25,
         issues: 25,
-        reviews: 10,
-        repos: 0,
-        stars: 50,
-        followers: 10,
+        reviews: 0,
+        repos: 25,
+        stars: 25,
+        followers: 25,
       }),
-    ).toStrictEqual({ level: "B+", percentile: 46.09375 });
+    ).toStrictEqual({ level: "A-", percentile: 27.55619360131255 });
   });
 
-  it("advanced user gets A rank", () => {
+  it("expert user gets A+ rank", () => {
     expect(
       calculateRank({
         all_commits: false,
         commits: 500,
         prs: 100,
-        issues: 50,
-        reviews: 20,
-        repos: 0,
-        stars: 200,
-        followers: 40,
-      }),
-    ).toStrictEqual({ level: "A", percentile: 20.841471354166664 });
-  });
-
-  it("expert user gets A+ rank", () => {
-    expect(
-      calculateRank({
-        all_commits: false,
-        commits: 1000,
-        prs: 200,
         issues: 100,
-        reviews: 40,
-        repos: 0,
-        stars: 800,
-        followers: 160,
+        reviews: 0,
+        repos: 100,
+        stars: 100,
+        followers: 100,
       }),
-    ).toStrictEqual({ level: "A+", percentile: 5.575988339442828 });
+    ).toStrictEqual({ level: "A+", percentile: 10.794579333709752 });
   });
 
   it("sindresorhus gets S rank", () => {
@@ -105,6 +90,6 @@ describe("Test calculateRank", () => {
         stars: 600000,
         followers: 50000,
       }),
-    ).toStrictEqual({ level: "S", percentile: 0.4578556547153667 });
+    ).toStrictEqual({ level: "S", percentile: 0.4312953010223719 });
   });
 });