chore: claude code refactor (7.5/10)

game.ts

@@ -33,6 +33,11 @@ export interface GameSession {
   bestStreak: number;
 }
 
+// Constants for word filtering
+const MIN_WORD_LENGTH = 3;
+const MAX_WORD_LENGTH = 8;
+const WORD_POOL_SIZE = 500;
+
 // Character sets for different difficulty levels
 const LETTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".split("");
 const NUMBERS = "0123456789".split("");
@@ -40,18 +45,32 @@ const PUNCTUATION = ".,?!-/()@".split("");
 const ALPHANUMERIC = [...LETTERS, ...NUMBERS];
 const FULL_SET = [...LETTERS, ...NUMBERS, ...PUNCTUATION];
 
+/**
+ * Fisher-Yates shuffle algorithm - O(n) complexity
+ */
+function shuffleArray<T>(array: T[]): T[] {
+  const shuffled = [...array];
+  for (let i = shuffled.length - 1; i > 0; i--) {
+    const j = Math.floor(Math.random() * (i + 1));
+    [shuffled[i], shuffled[j]] = [shuffled[j], shuffled[i]];
+  }
+  return shuffled;
+}
+
 // Filter words for morse code practice (3-8 letters, common words)
 const ALL_WORDS = wordsArray
   .filter((word: string) => {
     const upper = word.toUpperCase();
     return (
-      word.length >= 3 && word.length <= 8 && /^[A-Z]+$/.test(upper) // Only letters, no special chars
+      word.length >= MIN_WORD_LENGTH &&
+      word.length <= MAX_WORD_LENGTH &&
+      /^[A-Z]+$/.test(upper) // Only letters, no special chars
     );
   })
   .map((word: string) => word.toUpperCase());
 
-// Randomly select a subset for variety
-const WORDS = ALL_WORDS.sort(() => Math.random() - 0.5).slice(0, 500);
+// Randomly select a subset for variety using Fisher-Yates
+const WORDS = shuffleArray(ALL_WORDS).slice(0, WORD_POOL_SIZE);
 
 /**
  * Generate a random phrase from word combinations