fix(mailer): address copilot review comments

- Remove duplicate JSDoc block in ResendProvider.send()
- Add JSDoc to NodemailerProvider.send() with attachments params
- Fix content type annotation to string|Buffer in index.js and provider.resend.js
- Add provider.nodemailer.unit.tests.js covering attachments passthrough

Author: PierreBrisorgueil

lib/helpers/mailer/index.js

@@ -46,7 +46,7 @@ const isConfigured = () => !!(config.mailer && config.mailer.from && !String(con
  * @param {Object} mail.params - Template parameters
  * @param {Array} [mail.attachments] - Optional attachments array
  * @param {string} mail.attachments[].filename - Attachment filename
- * @param {string} mail.attachments[].content - Attachment content (string or Buffer)
+ * @param {string|Buffer} mail.attachments[].content - Attachment content (string or Buffer)
  * @returns {Promise<Object|null>} The send result or null if not configured
  */
 const sendMail = async (mail) => {

lib/helpers/mailer/provider.nodemailer.js

@@ -5,6 +5,18 @@ export default class NodemailerProvider {
     this.transport = nodemailer.createTransport(options);
   }
 
+  /**
+   * @desc Send an email via Nodemailer
+   * @param {Object} mail - Mail envelope
+   * @param {string} mail.from - Sender address
+   * @param {string} mail.to - Recipient address
+   * @param {string} mail.subject - Email subject
+   * @param {string} mail.html - HTML body
+   * @param {Array} [mail.attachments] - Optional attachments
+   * @param {string} mail.attachments[].filename - Filename
+   * @param {string|Buffer} mail.attachments[].content - Attachment content (string or Buffer)
+   * @returns {Promise<Object>} Nodemailer send result
+   */
   async send({ from, to, subject, html, attachments }) {
     const payload = { from, to, subject, html };
     if (attachments?.length) payload.attachments = attachments;

lib/helpers/mailer/provider.resend.js

@@ -19,9 +19,9 @@ export default class ResendProvider {
    * @param {string} mail.to - Recipient address
    * @param {string} mail.subject - Email subject
    * @param {string} mail.html - HTML body
-   * @param {Array} [mail.attachments] - Optional attachments array
-   * @param {string} mail.attachments[].filename - Attachment filename
-   * @param {string} mail.attachments[].content - Attachment content (string or Buffer)
+   * @param {Array} [mail.attachments] - Optional attachments
+   * @param {string} mail.attachments[].filename - Filename
+   * @param {string|Buffer} mail.attachments[].content - Content (string or Buffer)
    * @returns {Promise<Object>} Resend API response data
    */
   async send({ from, to, subject, html, attachments }) {

lib/helpers/mailer/tests/provider.nodemailer.unit.tests.js

@@ -0,0 +1,109 @@
+/**
+ * Module dependencies.
+ */
+import { jest, describe, test, expect, beforeEach } from '@jest/globals';
+
+// Mock nodemailer before importing the provider
+jest.unstable_mockModule('nodemailer', () => ({
+  default: {
+    createTransport: jest.fn(),
+  },
+}));
+
+const nodemailer = (await import('nodemailer')).default;
+const { default: NodemailerProvider } = await import('../provider.nodemailer.js');
+
+describe('NodemailerProvider unit tests:', () => {
+  let provider;
+  let sendMailMock;
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+    sendMailMock = jest.fn();
+    nodemailer.createTransport.mockReturnValue({ sendMail: sendMailMock });
+    provider = new NodemailerProvider({ host: 'smtp.example.com', port: 587 });
+  });
+
+  test('should create a nodemailer transport with provided options', () => {
+    expect(nodemailer.createTransport).toHaveBeenCalledWith({ host: 'smtp.example.com', port: 587 });
+  });
+
+  test('should send an email without attachments', async () => {
+    const mockResult = { messageId: 'msg_123' };
+    sendMailMock.mockResolvedValue(mockResult);
+
+    const result = await provider.send({
+      from: 'sender@example.com',
+      to: 'recipient@example.com',
+      subject: 'Test',
+      html: '<p>Hello</p>',
+    });
+
+    expect(sendMailMock).toHaveBeenCalledWith({
+      from: 'sender@example.com',
+      to: 'recipient@example.com',
+      subject: 'Test',
+      html: '<p>Hello</p>',
+    });
+    expect(result).toEqual(mockResult);
+  });
+
+  test('should send an email with attachments', async () => {
+    const mockResult = { messageId: 'msg_456' };
+    sendMailMock.mockResolvedValue(mockResult);
+
+    const csvContent = 'col1,col2\nval1,val2';
+    const result = await provider.send({
+      from: 'sender@example.com',
+      to: 'recipient@example.com',
+      subject: 'Test with attachment',
+      html: '<p>See attached</p>',
+      attachments: [{ filename: 'data.csv', content: csvContent }],
+    });
+
+    expect(sendMailMock).toHaveBeenCalledWith({
+      from: 'sender@example.com',
+      to: 'recipient@example.com',
+      subject: 'Test with attachment',
+      html: '<p>See attached</p>',
+      attachments: [{ filename: 'data.csv', content: csvContent }],
+    });
+    expect(result).toEqual(mockResult);
+  });
+
+  test('should not include attachments key when attachments array is empty', async () => {
+    const mockResult = { messageId: 'msg_789' };
+    sendMailMock.mockResolvedValue(mockResult);
+
+    await provider.send({
+      from: 'sender@example.com',
+      to: 'recipient@example.com',
+      subject: 'Test',
+      html: '<p>Hello</p>',
+      attachments: [],
+    });
+
+    const calledWith = sendMailMock.mock.calls[0][0];
+    expect(calledWith).not.toHaveProperty('attachments');
+  });
+
+  test('should send with Buffer attachment content', async () => {
+    const mockResult = { messageId: 'msg_buf' };
+    sendMailMock.mockResolvedValue(mockResult);
+
+    const bufContent = Buffer.from('binary data');
+    await provider.send({
+      from: 'sender@example.com',
+      to: 'recipient@example.com',
+      subject: 'Buffer test',
+      html: '<p>Buffer</p>',
+      attachments: [{ filename: 'file.bin', content: bufContent }],
+    });
+
+    expect(sendMailMock).toHaveBeenCalledWith(
+      expect.objectContaining({
+        attachments: [{ filename: 'file.bin', content: bufContent }],
+      }),
+    );
+  });
+});