refactor: centralize discord api errors

src/discord/api.test.ts

@@ -0,0 +1,42 @@
+import { describe, expect, it } from "vitest";
+
+import { fetchDiscord } from "./api.js";
+
+function jsonResponse(body: unknown, status = 200) {
+  return new Response(JSON.stringify(body), { status });
+}
+
+describe("fetchDiscord", () => {
+  it("formats rate limit payloads without raw JSON", async () => {
+    const fetcher = async () =>
+      jsonResponse(
+        {
+          message: "You are being rate limited.",
+          retry_after: 0.631,
+          global: false,
+        },
+        429,
+      );
+
+    let error: unknown;
+    try {
+      await fetchDiscord("/users/@me/guilds", "test", fetcher as typeof fetch);
+    } catch (err) {
+      error = err;
+    }
+
+    const message = String(error);
+    expect(message).toContain("Discord API /users/@me/guilds failed (429)");
+    expect(message).toContain("You are being rate limited.");
+    expect(message).toContain("retry after 0.6s");
+    expect(message).not.toContain("{");
+    expect(message).not.toContain("retry_after");
+  });
+
+  it("preserves non-JSON error text", async () => {
+    const fetcher = async () => new Response("Not Found", { status: 404 });
+    await expect(
+      fetchDiscord("/users/@me/guilds", "test", fetcher as typeof fetch),
+    ).rejects.toThrow("Discord API /users/@me/guilds failed (404): Not Found");
+  });
+});