refactor(telegram): share getChat id lookup helper

src/channels/telegram/api.test.ts

@@ -0,0 +1,56 @@
+import { describe, expect, it, vi } from "vitest";
+import { fetchTelegramChatId } from "./api.js";
+
+describe("fetchTelegramChatId", () => {
+  it("returns stringified id when Telegram getChat succeeds", async () => {
+    const fetchMock = vi.fn(async () => ({
+      ok: true,
+      json: async () => ({ ok: true, result: { id: 12345 } }),
+    }));
+    vi.stubGlobal("fetch", fetchMock);
+
+    const id = await fetchTelegramChatId({
+      token: "abc",
+      chatId: "@user",
+    });
+
+    expect(id).toBe("12345");
+    expect(fetchMock).toHaveBeenCalledWith(
+      "https://api.telegram.org/botabc/getChat?chat_id=%40user",
+      undefined,
+    );
+  });
+
+  it("returns null when response is not ok", async () => {
+    vi.stubGlobal(
+      "fetch",
+      vi.fn(async () => ({
+        ok: false,
+        json: async () => ({}),
+      })),
+    );
+
+    const id = await fetchTelegramChatId({
+      token: "abc",
+      chatId: "@user",
+    });
+
+    expect(id).toBeNull();
+  });
+
+  it("returns null on transport failures", async () => {
+    vi.stubGlobal(
+      "fetch",
+      vi.fn(async () => {
+        throw new Error("network failed");
+      }),
+    );
+
+    const id = await fetchTelegramChatId({
+      token: "abc",
+      chatId: "@user",
+    });
+
+    expect(id).toBeNull();
+  });
+});

src/channels/telegram/api.ts

@@ -0,0 +1,24 @@
+export async function fetchTelegramChatId(params: {
+  token: string;
+  chatId: string;
+  signal?: AbortSignal;
+}): Promise<string | null> {
+  const url = `https://api.telegram.org/bot${params.token}/getChat?chat_id=${encodeURIComponent(params.chatId)}`;
+  try {
+    const res = await fetch(url, params.signal ? { signal: params.signal } : undefined);
+    if (!res.ok) {
+      return null;
+    }
+    const data = (await res.json().catch(() => null)) as {
+      ok?: boolean;
+      result?: { id?: number | string };
+    } | null;
+    const id = data?.ok ? data?.result?.id : undefined;
+    if (typeof id === "number" || typeof id === "string") {
+      return String(id);
+    }
+    return null;
+  } catch {
+    return null;
+  }
+}