Closes #1179

src/cache.ts

@@ -170,6 +170,8 @@ export type CacheExecutor = (
 export function createExecute(cache: Cache): CacheExecutor {
   return function (type, options) {
     switch (type) {
+      case "FILTER_CATEGORY_CHILDREN_CHANNELS":
+        return cache.channels.filter(c => c.parentId === options.parentChannelId);
       case "DELETE_MESSAGES_FROM_CHANNEL":
         cache.messages.forEach((message) => {
           if (message.channelId === options.channelId) {

tests/helpers/channels/categoryChannels.ts

@@ -0,0 +1,40 @@
+import { Bot } from "../../../src/bot.ts";
+import { DiscordChannelTypes } from "../../../src/types/channels/channel_types.ts";
+import { assertExists } from "../../deps.ts";
+import { delayUntil } from "../../utils.ts";
+
+export async function categoryChildrenTest(bot: Bot, guildId: bigint, t: Deno.TestContext) {
+  const category = await bot.helpers.createChannel(guildId, {
+    name: "Discordeno-test",
+    type: DiscordChannelTypes.GuildCategory,
+  });
+
+  // Assertions
+  assertExists(category);
+  // Delay the execution to allow event to be processed
+  await delayUntil(10000, () => bot.cache.channels.has(category.id));
+
+  assertExists(bot.cache.channels.has(category.id));
+
+  const channelsToCreate = [1, 2, 3, 4, 5];
+  const channels = await Promise.all(
+    channelsToCreate.map((num) =>
+      bot.helpers.createChannel(guildId, {
+        name: `Discordeno-test-${num}`,
+        parentId: category.id,
+      })
+    )
+  );
+  // Delay the execution to allow event to be processed
+  await delayUntil(10000, () => channels.every((c) => bot.cache.channels.has(c.id)));
+
+  // If every channel is not present in the cache, error out
+  if (!channels.every((c) => bot.cache.channels.has(c.id))) {
+    throw new Error("The channels seemed to be created but it was not cached.");
+  }
+
+  const ids = await bot.helpers.categoryChildren(category.id);
+  if (ids.size !== channelsToCreate.length || !channels.every((c) => ids.has(c.id))) {
+    throw new Error("The category channel ids did not match with the category channels.");
+  }
+}