Merge pull request #37 from StefanWin/main

allow simple labels in test email addresses

Author: ianmacartney

README.md

@@ -67,6 +67,10 @@ Then, calling `sendTestEmail` from anywhere in your app will send this test emai
 If you want to send emails to real addresses, you need to disable `testMode`.
 You can do this in `ResendOptions`, [as detailed below](#resend-component-options-and-going-into-production).
 
+A note on test email addresses:
+[Resend allows the use of labels](https://resend.com/docs/dashboard/emails/send-test-emails#using-labels-effectively) for test emails. 
+For simplicity, this component only allows labels matching `[a-zA-Z0-9_-]*`, e.g. `[email protected]`.
+
 ## Advanced Usage
 
 ### Setting up a Resend webhook

src/component/lib.ts

@@ -24,7 +24,7 @@ import { isDeepEqual } from "remeda";
 import schema from "./schema.js";
 import { omit } from "convex-helpers";
 import { parse } from "convex-helpers/validators";
-import { assertExhaustive, attemptToParse, iife } from "./utils.js";
+import { assertExhaustive, attemptToParse, iife, isValidResendTestEmail } from "./utils.js";
 
 // Move some of these to options? TODO
 const SEGMENT_MS = 125;
@@ -37,12 +37,6 @@ const FINALIZED_EMAIL_RETENTION_MS = 1000 * 60 * 60 * 24 * 7; // 7 days
 const FINALIZED_EPOCH = Number.MAX_SAFE_INTEGER;
 const ABANDONED_EMAIL_RETENTION_MS = 1000 * 60 * 60 * 24 * 30; // 30 days
 
-const RESEND_TEST_EMAILS = new Set([
-  "[email protected]",
-  "[email protected]",
-  "[email protected]",
-]);
-
 const PERMANENT_ERROR_CODES = new Set([
   400, 401 /* 402 not included - unclear spec */, 403, 404, 405, 406, 407, 408,
   /* 409 not included - conflict may work on retry */
@@ -100,7 +94,7 @@ export const sendEmail = mutation({
   returns: v.id("emails"),
   handler: async (ctx, args) => {
     // We only allow test emails in test mode.
-    if (args.options.testMode && !RESEND_TEST_EMAILS.has(args.to)) {
+    if (args.options.testMode && !isValidResendTestEmail(args.to)) {
       throw new Error(
         `Test mode is enabled, but email address is not a valid resend test address. Did you want to set testMode: false in your ResendOptions?`
       );

src/component/utils.test.ts

@@ -0,0 +1,33 @@
+import { describe, it, expect } from "vitest";
+import { isValidResendTestEmail } from "./utils.js";
+
+describe("isValidResendTestEmail", () => {
+
+  it("allows valid test emails without labels", () => {
+    expect(isValidResendTestEmail("[email protected]")).toBe(true);
+    expect(isValidResendTestEmail("[email protected]")).toBe(true);
+    expect(isValidResendTestEmail("[email protected]")).toBe(true);
+  });
+
+  it("allows valid test emails with labels", () => {
+    expect(isValidResendTestEmail("[email protected]")).toBe(true);
+    expect(isValidResendTestEmail("[email protected]")).toBe(true);
+    expect(isValidResendTestEmail("[email protected]")).toBe(true);
+    expect(isValidResendTestEmail("[email protected]")).toBe(true);
+    expect(isValidResendTestEmail("[email protected]")).toBe(true);
+    expect(isValidResendTestEmail("[email protected]")).toBe(true);
+  });
+
+  it("rejects invalid test emails with or without labels", () => {
+    expect(isValidResendTestEmail("[email protected]")).toBe(false);
+    expect(isValidResendTestEmail("[email protected]")).toBe(false);
+    expect(isValidResendTestEmail("[email protected]")).toBe(false);
+  });
+
+  it("rejects test emails with disallowed special characters in the label", () => {
+    expect(isValidResendTestEmail("[email protected]")).toBe(false);
+    expect(isValidResendTestEmail("bounced+user/[email protected]")).toBe(false);
+    expect(isValidResendTestEmail("[email protected]")).toBe(false);
+  });
+
+});

src/component/utils.ts

@@ -27,3 +27,19 @@ export function attemptToParse<T extends Validator<any, any, any>>(
     };
   }
 }
+
+/**
+ * This is one is intentionally kept simple and only allows - and _ as special characters
+ * since Resend does not specify what pattern a label must follow, the documentation
+ * only says "any string": https://resend.com/docs/dashboard/emails/send-test-emails#using-labels-effectively
+ * and a full RFC-5322 compliant regex would be way too long.
+ */
+const RESEND_TEST_EMAIL_REGEX = /^(delivered|bounced|complained)(\+[a-zA-Z0-9_-]*)?@resend\.dev$/;
+
+/**
+ * Check if the given e-mail address is a valid test e-mail for Resend.
+ * @param email
+ */
+export function isValidResendTestEmail(email: string): boolean {
+  return RESEND_TEST_EMAIL_REGEX.test(email);
+}