refactor(curriculum): drop string-similarity

curriculum/package.json

@@ -65,7 +65,6 @@
     "@types/debug": "4.1.12",
     "@types/js-yaml": "4.0.5",
     "@types/polka": "0.5.7",
-    "@types/string-similarity": "4.0.2",
     "@typescript/vfs-1.6.1": "npm:@typescript/vfs@1.6.4",
     "@vitest/ui": "4.0.15",
     "eslint": "9.39.1",
@@ -81,7 +80,6 @@
     "polka": "0.5.2",
     "puppeteer": "22.12.1",
     "sirv": "3.0.2",
-    "string-similarity": "4.0.4",
     "typescript-5.9.2": "npm:typescript@5.9.2",
     "vitest": "4.0.15"
   },

curriculum/src/filter.ts

@@ -1,5 +1,3 @@
-import comparison from 'string-similarity';
-
 /**
  * Filters the superblocks array to include any superblocks with the specified block.
  * If no block is provided, returns the original superblocks array.
@@ -125,8 +123,74 @@ export const applyFilters: GenericFilterFunction = createFilterPipeline([
   filterByChallengeId
 ]);
 
+function normalizeForComparison(value: string): string {
+  return value.toLowerCase().replace(/[^a-z0-9]+/g, '');
+}
+
+function createBigrams(value: string): Map<string, number> {
+  const bigrams = new Map<string, number>();
+
+  for (let i = 0; i < value.length - 1; i++) {
+    const bigram = value.slice(i, i + 2);
+    bigrams.set(bigram, (bigrams.get(bigram) ?? 0) + 1);
+  }
+
+  return bigrams;
+}
+
+function getSimilarityScore(a: string, b: string): number {
+  if (a === b) {
+    return 1;
+  }
+
+  if (a.length < 2 || b.length < 2) {
+    return 0;
+  }
+
+  const aBigrams = createBigrams(a);
+  let intersection = 0;
+
+  for (let i = 0; i < b.length - 1; i++) {
+    const bigram = b.slice(i, i + 2);
+    const count = aBigrams.get(bigram);
+
+    if (count) {
+      intersection += 1;
+      aBigrams.set(bigram, count - 1);
+    }
+  }
+
+  return (2 * intersection) / (a.length + b.length - 2);
+}
+
 export function closestMatch(target: string, xs: string[]): string {
-  return comparison.findBestMatch(target.toLowerCase(), xs).bestMatch.target;
+  const [firstCandidate, ...rest] = xs;
+
+  if (!firstCandidate) {
+    return target;
+  }
+
+  const normalizedTarget = normalizeForComparison(target);
+
+  let closest = firstCandidate;
+  let closestScore = getSimilarityScore(
+    normalizedTarget,
+    normalizeForComparison(closest)
+  );
+
+  for (const candidate of rest) {
+    const score = getSimilarityScore(
+      normalizedTarget,
+      normalizeForComparison(candidate)
+    );
+
+    if (score > closestScore) {
+      closest = candidate;
+      closestScore = score;
+    }
+  }
+
+  return closest;
 }
 
 export function closestFilters(

pnpm-lock.yaml

@@ -716,9 +716,6 @@ importers:
       '@types/polka':
         specifier: 0.5.7
         version: 0.5.7
-      '@types/string-similarity':
-        specifier: 4.0.2
-        version: 4.0.2
       '@typescript/vfs-1.6.1':
         specifier: npm:@typescript/vfs@1.6.4
         version: '@typescript/vfs@1.6.4(typescript@5.9.3)'
@@ -764,9 +761,6 @@ importers:
       sirv:
         specifier: 3.0.2
         version: 3.0.2
-      string-similarity:
-        specifier: 4.0.4
-        version: 4.0.4
       typescript-5.9.2:
         specifier: npm:typescript@5.9.2
         version: typescript@5.9.2
@@ -4911,9 +4905,6 @@ packages:
   '@types/store@2.0.5':
     resolution: {integrity: sha512-5NmTKe3GWdOaykzq7no+Ahf6mafJu0oLc9JNhJ3E26+0oFvd6GnksnZQpMXcH526mfG4xDYjFiKzyDL51PzeWQ==}
 
-  '@types/string-similarity@4.0.2':
-    resolution: {integrity: sha512-LkJQ/jsXtCVMK+sKYAmX/8zEq+/46f1PTQw7YtmQwb74jemS1SlNLmARM2Zml9DgdDTWKAtc5L13WorpHPDjDA==}
-
   '@types/superagent@4.1.19':
     resolution: {integrity: sha512-McM1mlc7PBZpCaw0fw/36uFqo0YeA6m8JqoyE4OfqXsZCIg0hPP2xdE6FM7r6fdprDZHlJwDpydUj1R++93hCA==}
 
@@ -11819,10 +11810,6 @@ packages:
     resolution: {integrity: sha512-IoHUjcw3Srl8nsPlW04U3qwWPk3oG2ffLM0tN853d/E/JlIvcmZmDY2Kz5HzKp4lEi2T7QD7Zuvjq/1rDw+XcQ==}
     deprecated: Package no longer supported. Contact Support at https://www.npmjs.com/support for more info.
 
-  string-similarity@4.0.4:
-    resolution: {integrity: sha512-/q/8Q4Bl4ZKAPjj8WerIBJWALKkaPRfrvhfF8k/B23i4nzrlRj2/go1m90In7nG/3XDSbOo0+pu6RvCTM9RGMQ==}
-    deprecated: Package no longer supported. Contact Support at https://www.npmjs.com/support for more info.
-
   string-width@4.2.3:
     resolution: {integrity: sha512-wKyQRQpjJ0sIp62ErSZdGsjMJWsap5oRNihHhu6G7JVO/9jIB6UyevL+tXuOqrng8j/cxKTWyWUwvSTriiZz/g==}
     engines: {node: '>=8'}
@@ -18482,8 +18469,6 @@ snapshots:
 
   '@types/store@2.0.5': {}
 
-  '@types/string-similarity@4.0.2': {}
-
   '@types/superagent@4.1.19':
     dependencies:
       '@types/cookiejar': 2.1.2
@@ -18908,7 +18893,7 @@ snapshots:
       sirv: 3.0.2
       tinyglobby: 0.2.15
       tinyrainbow: 3.0.3
-      vitest: 4.0.15(@opentelemetry/api@1.9.0)(@types/node@25.5.0)(@vitest/ui@4.0.15)(jiti@2.6.1)(jsdom@26.1.0)(msw@2.13.2(@types/node@25.5.0)(typescript@5.9.3))(terser@5.46.0)(tsx@4.21.0)(yaml@2.8.1)
+      vitest: 4.0.15(@opentelemetry/api@1.9.0)(@types/node@24.10.8)(@vitest/ui@4.0.15)(jiti@2.6.1)(jsdom@16.7.0)(msw@2.13.2(@types/node@24.10.8)(typescript@5.9.3))(terser@5.46.0)(tsx@4.21.0)(yaml@2.8.1)
 
   '@vitest/utils@3.2.4':
     dependencies:
@@ -27133,8 +27118,6 @@ snapshots:
       lodash.map: 4.6.0
       lodash.maxby: 4.6.0
 
-  string-similarity@4.0.4: {}
-
   string-width@4.2.3:
     dependencies:
       emoji-regex: 8.0.0