From 32414d8b93fba93836e1df9860494ca37bac706b Mon Sep 17 00:00:00 2001
From: Justin Ridgewell <justin@ridgewell.name>
Date: Thu, 29 Feb 2024 00:57:41 -0500
Subject: [PATCH] Add remove API

---
 src/set-array.ts       | 17 +++++++++++++
 test/set-array.test.ts | 57 +++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 73 insertions(+), 1 deletion(-)

diff --git a/src/set-array.ts b/src/set-array.ts
index 86e6cbf..c05926e 100644
--- a/src/set-array.ts
+++ b/src/set-array.ts
@@ -63,3 +63,20 @@ export function pop<T extends Key>(setarr: SetArray<T>): void {
   const last = array.pop()!;
   indexes[last] = undefined;
 }
+
+/**
+ * Removes the key, if it exists in the set.
+ */
+export function remove<T extends Key>(setarr: SetArray<T>, key: T): void {
+  const index = get(setarr, key);
+  if (index === undefined) return;
+
+  const { array, _indexes: indexes } = cast(setarr);
+  for (let i = index + 1; i < array.length; i++) {
+    const k = array[i];
+    array[i - 1] = k;
+    indexes[k]!--;
+  }
+  indexes[key] = undefined;
+  array.pop();
+}
diff --git a/test/set-array.test.ts b/test/set-array.test.ts
index f783f5e..155113d 100644
--- a/test/set-array.test.ts
+++ b/test/set-array.test.ts
@@ -1,4 +1,4 @@
-import { SetArray, get, put, pop } from '../src/set-array';
+import { SetArray, get, put, pop, remove } from '../src/set-array';
 import { strict as assert } from 'assert';
 
 describe('SetArray', () => {
@@ -111,4 +111,59 @@ describe('SetArray', () => {
       assert.equal(get(array, 'foo'), 0);
     });
   });
+
+  describe('remove()', () => {
+    it('removes item from array', () => {
+      const array = new SetArray();
+
+      put(array, 'test');
+      put(array, 'foo');
+      put(array, 'bar');
+
+      remove(array, 'foo');
+      assert.deepEqual(array.array, ['test', 'bar']);
+      remove(array, 'bar');
+      assert.deepEqual(array.array, ['test']);
+      remove(array, 'test');
+      assert.deepEqual(array.array, []);
+    });
+
+    it('unsets the key', () => {
+      const array = new SetArray();
+
+      put(array, 'test');
+      remove(array, 'test');
+      assert.equal(get(array, 'test'), undefined);
+    });
+
+    it('updates indexes of following keys', () => {
+      const array = new SetArray();
+
+      put(array, 'test');
+      put(array, 'foo');
+      put(array, 'bar');
+
+      remove(array, 'foo');
+      assert.equal(get(array, 'test'), 0);
+      assert.equal(get(array, 'bar'), 1);
+    });
+
+    it('putting afterwards writes to array at old index', () => {
+      const array = new SetArray();
+
+      put(array, 'test');
+      remove(array, 'test');
+      put(array, 'foo');
+      assert.deepEqual(array.array, ['foo']);
+    });
+
+    it('getting after put gets old key ', () => {
+      const array = new SetArray();
+
+      put(array, 'test');
+      remove(array, 'test');
+      put(array, 'foo');
+      assert.equal(get(array, 'foo'), 0);
+    });
+  });
 });