fix: only pick from the unshuffled portion

radashi-org · Jan 9, 2025 · 16fec8e · 16fec8e
1 parent fd3ddea
commit 16fec8e
Showing 1 changed file with 5 additions and 5 deletions.
diff --git a/src/random/shuffle.ts b/src/random/shuffle.ts
@@ -38,11 +38,11 @@ export function shuffle<T>(
   random: (min: number, max: number) => number = _.random,
 ): T[] {
   const newArray = array.slice()
-  for (let idx = 0, randomIdx: number, item: T; idx < array.length; idx++) {
-    randomIdx = random(0, array.length - 1)
-    item = newArray[randomIdx]
-    newArray[randomIdx] = newArray[idx]
-    newArray[idx] = item
+  for (let idx = array.length - 1, randomIdx: number, item: T; idx > 0; idx--) {
+    randomIdx = random(0, idx)
+    item = newArray[idx]
+    newArray[idx] = newArray[randomIdx]
+    newArray[randomIdx] = item
   }
   return newArray
 }