fix: detect spam

package.json

@@ -15,7 +15,8 @@
     "serve": "cross-env NODE_OPTIONS=--no-deprecation next start",
     "storybook": "storybook dev -p 6006",
     "build-storybook": "storybook build",
-    "chromatic": "npx chromatic --project-token=chpt_70d6a2e05af185a"
+    "chromatic": "npx chromatic --project-token=chpt_70d6a2e05af185a",
+    "test": "vitest"
   },
   "dependencies": {
     "@payloadcms/db-postgres": "^3.22.0",
@@ -25,6 +26,7 @@
     "classnames": "^2.5.1",
     "cross-env": "^7.0.3",
     "graphql": "^16.8.1",
+    "languagedetect": "^2.0.0",
     "moment": "^2.30.1",
     "next": "15.1.2",
     "payload": "^3.22.0",
@@ -56,7 +58,8 @@
     "eslint-config-prettier": "^9.1.0",
     "eslint-plugin-storybook": "^0.8.0",
     "storybook": "^8.2.9",
-    "typescript": "5.5.4"
+    "typescript": "5.5.4",
+    "vitest": "^3.1.1"
   },
   "engines": {
     "node": "^18.20.2 || >=20.9.0"

src/utils/actions.ts

@@ -2,6 +2,7 @@
 
 import { z } from 'zod'
 import { Resend } from 'resend'
+import { isSpam } from '@/utils/detectSpam'
 
 /**
  * Send email through Resend API
@@ -32,6 +33,12 @@ export async function send(prevState: any, formData: FormData) {
     }
   }
 
+  if (isSpam(validatedFields.data.message)) {
+    return {
+      message: "Ihre Nachricht wurde als unerwünschte Werbung eingestuft und nicht gesendet."
+    }
+  }
+
   try {
     const resend = new Resend(process.env.RESEND_API_KEY);
     const resp = await resend.emails.send({

src/utils/detectSpam.test.ts

@@ -0,0 +1,28 @@
+import { isSpam } from './detectSpam';
+import { describe, it, expect } from 'vitest'
+
+describe('isSpam function', () => {
+  it('should classify a message containing a URL as spam', () => {
+  const spamMessage = "Check out this site for amazing deals https://www.spamsite.com";
+  const result = isSpam(spamMessage);
+  expect(result).toBe(true);
+  });
+
+  it('should not classify a German message without a URL as spam', () => {
+  const nonSpamMessage = "Das ist eine Nachricht ohne URL";
+  const result = isSpam(nonSpamMessage);
+  expect(result).toBe(false);
+  });
+
+  it('should not classify a English message without a URL as spam', () => {
+    const nonSpamMessage = "Hi, this is some message";
+    const result = isSpam(nonSpamMessage);
+    expect(result).toBe(false);
+  });
+
+  it('should not classify a German message with a URL as spam', () => {
+  const spamMessage = "Schauen Sie sich diese Website für tolle Angebote an https://www.spamsite.com";
+  const result = isSpam(spamMessage);
+  expect(result).toBe(false);
+  });
+});

src/utils/detectSpam.ts

@@ -0,0 +1,21 @@
+import LanguageDetect from 'languagedetect'
+
+/**
+ * This function determines whether a given message can be classified as spam.
+ *
+ * A message is classified as spam based on the following criteria:
+ *   1. The message contains a URL i.e., it includes `https://`.
+ *   2. The message is not written in the German language.
+ *
+ * Returns a boolean value indicating whether the message is spam (`true`) or not (`false`).
+ */
+export const isSpam = (message: string): boolean => {
+
+  if (message.includes('https://')) {
+      const lngDetector = new LanguageDetect();
+      const language = lngDetector.detect(message)[0][0];
+      return language !== 'german';
+  }
+
+  return false;
+}