From 8c1d4d1f41da8c71817682ce5e4434e67032a269 Mon Sep 17 00:00:00 2001
From: Michael Beckemeyer <m.beckemeyer@conterra.de>
Date: Fri, 4 Oct 2024 12:17:11 +0200
Subject: [PATCH] Add missing forEach methods

---
 packages/reactivity-core/CHANGELOG.md         |  1 +
 .../reactivity-core/collections/map.test.ts   | 30 ++++++++++++++++++-
 packages/reactivity-core/collections/map.ts   | 15 ++++++++++
 .../reactivity-core/collections/set.test.ts   | 27 ++++++++++++++++-
 packages/reactivity-core/collections/set.ts   | 11 +++++++
 5 files changed, 82 insertions(+), 2 deletions(-)

diff --git a/packages/reactivity-core/CHANGELOG.md b/packages/reactivity-core/CHANGELOG.md
index c9e7222..6a736d5 100644
--- a/packages/reactivity-core/CHANGELOG.md
+++ b/packages/reactivity-core/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## v0.4.3 (Unreleased)
 
 -   Introduce `subtleWatchDirty`, a function that allows one to watch for signal changes without triggering the re-evaluation of the signal.
+-   Add missing `forEach()` method to `ReactiveSet` and `ReactiveMap`.
 -   Deprecate `syncEffectOnce` (use `subtleWatchDirty` instead).
 
 ## v0.4.2
diff --git a/packages/reactivity-core/collections/map.test.ts b/packages/reactivity-core/collections/map.test.ts
index 095f891..719d3c8 100644
--- a/packages/reactivity-core/collections/map.test.ts
+++ b/packages/reactivity-core/collections/map.test.ts
@@ -1,4 +1,4 @@
-import { it, expect, describe } from "vitest";
+import { it, expect, describe, vi } from "vitest";
 import { ReactiveMap, reactiveMap } from "./map";
 import { batch, computed } from "../ReactiveImpl";
 import { syncEffect } from "../sync";
@@ -45,6 +45,34 @@ describe("basic API", () => {
         expect(removed).toBe(false);
     });
 
+    it("supports iteration via forEach", () => {
+        const map = reactiveMap<string, number>([
+            ["foo", 1],
+            ["bar", 2]
+        ]);
+        map.set("baz", 3);
+
+        const cb = vi.fn();
+        map.forEach(cb);
+
+        expect(cb.mock.calls).toMatchInlineSnapshot(`
+          [
+            [
+              1,
+              "foo",
+            ],
+            [
+              2,
+              "bar",
+            ],
+            [
+              3,
+              "baz",
+            ],
+          ]
+        `);
+    });
+
     it("supports iteration", () => {
         const map = reactiveMap<string, number>([
             ["foo", 1],
diff --git a/packages/reactivity-core/collections/map.ts b/packages/reactivity-core/collections/map.ts
index 68afb89..acb3f81 100644
--- a/packages/reactivity-core/collections/map.ts
+++ b/packages/reactivity-core/collections/map.ts
@@ -42,6 +42,13 @@ export interface ReactiveMap<K, V> extends Iterable<[key: K, value: V]> {
      */
     delete(key: K): boolean;
 
+    /**
+     * Executes the given callback for every entry of the map.
+     *
+     * See also [Map.forEach](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/forEach).
+     */
+    forEach(callback: (value: V, key: K) => void): void;
+
     /**
      * Returns an iterator over the `[key, value]` entries in this map.
      */
@@ -108,6 +115,14 @@ class ReactiveMapImpl<K, V> implements ReactiveMap<K, V> {
         return this.#map.size;
     }
 
+    forEach(callback: (value: V, key: K) => void): void {
+        this.#subscribeToStructureChange();
+        const entries = this.#map.entries();
+        for (const [key, cell] of entries) {
+            callback(cell.value, key);
+        }
+    }
+
     entries(): IterableIterator<[K, V]> {
         this.#subscribeToStructureChange();
         return this.#iterateEntries();
diff --git a/packages/reactivity-core/collections/set.test.ts b/packages/reactivity-core/collections/set.test.ts
index 7b212fb..8390894 100644
--- a/packages/reactivity-core/collections/set.test.ts
+++ b/packages/reactivity-core/collections/set.test.ts
@@ -1,4 +1,4 @@
-import { it, expect, describe } from "vitest";
+import { it, expect, describe, vi } from "vitest";
 import { reactiveSet } from "./set";
 
 describe("basic API", () => {
@@ -31,6 +31,31 @@ describe("basic API", () => {
         expect(removed).toBe(false);
     });
 
+    it("supports iteration via forEach", () => {
+        const set = reactiveSet<string>(["foo", "bar"]);
+        set.add("baz");
+
+        const cb = vi.fn();
+        set.forEach(cb);
+
+        expect(cb.mock.calls).toMatchInlineSnapshot(`
+        [
+          [
+            "foo",
+            "foo",
+          ],
+          [
+            "bar",
+            "bar",
+          ],
+          [
+            "baz",
+            "baz",
+          ],
+        ]
+      `);
+    });
+
     it("supports iteration", () => {
         const set = reactiveSet<string>(["foo", "bar"]);
         set.add("baz");
diff --git a/packages/reactivity-core/collections/set.ts b/packages/reactivity-core/collections/set.ts
index 4cdbc54..1aec460 100644
--- a/packages/reactivity-core/collections/set.ts
+++ b/packages/reactivity-core/collections/set.ts
@@ -36,6 +36,13 @@ export interface ReactiveSet<V> extends Iterable<V> {
      */
     delete(value: V): boolean;
 
+    /**
+     * Executes the given callback for every entry of the set.
+     *
+     * See also [Set.forEach](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/forEach).
+     */
+    forEach(callback: (value: V, key: V) => void): void;
+
     /**
      * Returns an iterator over the `[value, value]` entries in this set.
      *
@@ -110,6 +117,10 @@ export class ReactiveSetImpl<V> implements ReactiveSet<V> {
         return this.#impl.delete(value);
     }
 
+    forEach(callback: (value: V, key: V) => void): void {
+        this.#impl.forEach((_value, key) => callback(key, key));
+    }
+
     entries(): IterableIterator<[value: V, value: V]> {
         return mapToDuplicateEntries(this.values());
     }