From f57452ece2db1521bc473cc212fce0661c428b7d Mon Sep 17 00:00:00 2001
From: Chris Wanstrath <chris@ozmm.org>
Date: Sat, 8 Nov 2025 08:14:46 -0800
Subject: [PATCH] list.reject

---
 src/prelude/list.ts               | 7 +++++++
 src/prelude/tests/prelude.test.ts | 9 +++++++++
 2 files changed, 16 insertions(+)

diff --git a/src/prelude/list.ts b/src/prelude/list.ts
index 1f0ec76..8e861b9 100644
--- a/src/prelude/list.ts
+++ b/src/prelude/list.ts
@@ -14,6 +14,13 @@ export const list = {
     }
     return acc
   },
+  reject: async (list: any[], cb: Function) => {
+    let acc: any[] = []
+    for (const value of list) {
+      if (!(await cb(value))) acc.push(value)
+    }
+    return acc
+  },
   reduce: async (list: any[], cb: Function, initial: any) => {
     let acc = initial
     for (const value of list) acc = await cb(acc, value)
diff --git a/src/prelude/tests/prelude.test.ts b/src/prelude/tests/prelude.test.ts
index 04ceb8b..069b174 100644
--- a/src/prelude/tests/prelude.test.ts
+++ b/src/prelude/tests/prelude.test.ts
@@ -193,6 +193,15 @@ describe('collections', () => {
     `).toEvaluateTo([3, 4, 5])
   })
 
+  test('list.reject doesnt keep matching elements', async () => {
+    await expect(`
+      is-even = do x:
+        (x % 2) == 0
+      end
+      list.reject [1 2 3 4 5] is-even
+    `).toEvaluateTo([1, 3, 5])
+  })
+
   test('list.reduce accumulates values', async () => {
     await expect(`
       add = do acc x: