Support custom ID types (string/number) for improved compatibility

- Replace hardcoded payload-types imports with generic BaseEmailDocument interface
- Update sendEmail and sendEmailTask to work with both string and number IDs
- Refactor MailingService to use generic document types instead of specific ones
- Add BaseEmailDocument and BaseEmailTemplateDocument interfaces supporting id: string | number
- Export BaseEmailDocument for users to extend with their custom fields
- Fix TypeScript compilation error in template subject handling
- Add CUSTOM-TYPES.md documentation for users with different ID types

Fixes compatibility issue where plugin required number IDs but user projects used string IDs.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

CUSTOM-TYPES.md

@@ -0,0 +1,88 @@
+# Using Custom ID Types
+
+The mailing plugin now supports both `string` and `number` ID types. By default, it works with the generic `BaseEmailDocument` interface, but you can provide your own types for full type safety.
+
+## Usage with Your Generated Types
+
+When you have your own generated Payload types (e.g., from `payload generate:types`), you can use them with the mailing plugin:
+
+```typescript
+import { sendEmail, BaseEmailDocument } from '@xtr-dev/payload-mailing'
+import { Email } from './payload-types' // Your generated types
+
+// Option 1: Use your specific Email type
+const email = await sendEmail<Email>(payload, {
+  template: {
+    slug: 'welcome',
+    variables: { name: 'John' }
+  },
+  data: {
+    to: 'user@example.com',
+    // All your custom fields are now type-safe
+  }
+})
+
+// Option 2: Extend BaseEmailDocument for custom fields
+interface MyEmail extends BaseEmailDocument {
+  customField: string
+  anotherField?: number
+}
+
+const customEmail = await sendEmail<MyEmail>(payload, {
+  data: {
+    to: 'user@example.com',
+    subject: 'Hello',
+    html: '<p>Hello World</p>',
+    customField: 'my value', // Type-safe!
+  }
+})
+```
+
+## ID Type Compatibility
+
+The plugin works with both:
+- **String IDs**: `id: string`
+- **Number IDs**: `id: number`
+
+Your Payload configuration determines which type is used. The plugin automatically adapts to your setup.
+
+## Type Definitions
+
+The base interfaces provided by the plugin:
+
+```typescript
+interface BaseEmailDocument {
+  id: string | number
+  template?: any
+  to: string[]
+  cc?: string[]
+  bcc?: string[]
+  from?: string
+  replyTo?: string
+  subject: string
+  html: string
+  text?: string
+  variables?: Record<string, any>
+  scheduledAt?: string
+  sentAt?: string
+  status?: 'pending' | 'processing' | 'sent' | 'failed'
+  attempts?: number
+  lastAttemptAt?: string
+  error?: string
+  priority?: number
+  createdAt?: string
+  updatedAt?: string
+}
+
+interface BaseEmailTemplateDocument {
+  id: string | number
+  name: string
+  slug: string
+  subject?: string
+  content?: any
+  createdAt?: string
+  updatedAt?: string
+}
+```
+
+These provide a foundation that works with any ID type while maintaining type safety for the core email functionality.

src/index.ts

@@ -16,7 +16,7 @@ export { mailingJobs, sendEmailJob } from './jobs/index.js'
 export type { SendEmailTaskInput } from './jobs/sendEmailTask.js'
 
 // Main email sending function
-export { sendEmail, type SendEmailOptions } from './sendEmail.js'
+export { sendEmail, type SendEmailOptions, type BaseEmailDocument } from './sendEmail.js'
 export { default as sendEmailDefault } from './sendEmail.js'
 
 // Utility functions for developers

src/jobs/sendEmailTask.ts

@@ -1,5 +1,4 @@
-import { sendEmail } from '../sendEmail.js'
-import {Email, EmailTemplate} from '../payload-types.js'
+import { sendEmail, BaseEmailDocument } from '../sendEmail.js'
 
 export interface SendEmailTaskInput {
   // Template mode fields
@@ -170,7 +169,7 @@ export const sendEmailJob = {
       const sendEmailOptions = transformTaskInputToSendEmailOptions(taskInput)
 
       // Use the sendEmail helper to create the email
-      const email = await sendEmail<Email>(payload, sendEmailOptions)
+      const email = await sendEmail<BaseEmailDocument>(payload, sendEmailOptions)
 
       return {
         output: {

src/sendEmail.ts

@@ -1,9 +1,32 @@
 import { Payload } from 'payload'
 import { getMailing, renderTemplate, parseAndValidateEmails } from './utils/helpers.js'
-import {Email, EmailTemplate} from "./payload-types.js"
+
+// Generic email interface that can work with any ID type
+export interface BaseEmailDocument {
+  id: string | number
+  template?: any
+  to: string[]
+  cc?: string[]
+  bcc?: string[]
+  from?: string
+  replyTo?: string
+  subject: string
+  html: string
+  text?: string
+  variables?: Record<string, any>
+  scheduledAt?: string
+  sentAt?: string
+  status?: 'pending' | 'processing' | 'sent' | 'failed'
+  attempts?: number
+  lastAttemptAt?: string
+  error?: string
+  priority?: number
+  createdAt?: string
+  updatedAt?: string
+}
 
 // Options for sending emails
-export interface SendEmailOptions<T extends Email = Email> {
+export interface SendEmailOptions<T extends BaseEmailDocument = BaseEmailDocument> {
   // Template-based email
   template?: {
     slug: string
@@ -35,7 +58,7 @@ export interface SendEmailOptions<T extends Email = Email> {
  * })
  * ```
  */
-export const sendEmail = async <TEmail extends Email = Email>(
+export const sendEmail = async <TEmail extends BaseEmailDocument = BaseEmailDocument>(
   payload: Payload,
   options: SendEmailOptions<TEmail>
 ): Promise<TEmail> => {

src/services/MailingService.ts

@@ -6,7 +6,7 @@ import {
   TemplateVariables,
   MailingService as IMailingService,
   MailingTransportConfig,
-  BaseEmail, BaseEmailTemplate
+  BaseEmail, BaseEmailTemplate, BaseEmailDocument, BaseEmailTemplateDocument
 } from '../types/index.js'
 import { serializeRichTextToHTML, serializeRichTextToText } from '../utils/richTextSerializer.js'
 
@@ -131,7 +131,7 @@ export class MailingService implements IMailingService {
     }
 
     const emailContent = await this.renderEmailTemplate(template, variables)
-    const subject = await this.renderTemplateString(template.subject, variables)
+    const subject = await this.renderTemplateString(template.subject || '', variables)
 
     return {
       html: emailContent.html,
@@ -236,7 +236,7 @@ export class MailingService implements IMailingService {
       const email = await this.payload.findByID({
         collection: this.emailsCollection as any,
         id: emailId,
-      }) as BaseEmail
+      }) as BaseEmailDocument
 
       const mailOptions = {
         from: email.from,
@@ -300,7 +300,7 @@ export class MailingService implements IMailingService {
     return newAttempts
   }
 
-  private async getTemplateBySlug(templateSlug: string): Promise<BaseEmailTemplate | null> {
+  private async getTemplateBySlug(templateSlug: string): Promise<BaseEmailTemplateDocument | null> {
     try {
       const { docs } = await this.payload.find({
         collection: this.templatesCollection as any,
@@ -312,7 +312,7 @@ export class MailingService implements IMailingService {
         limit: 1,
       })
 
-      return docs.length > 0 ? docs[0] as BaseEmailTemplate : null
+      return docs.length > 0 ? docs[0] as BaseEmailTemplateDocument : null
     } catch (error) {
       console.error(`Template with slug '${templateSlug}' not found:`, error)
       return null
@@ -377,7 +377,7 @@ export class MailingService implements IMailingService {
     })
   }
 
-  private async renderEmailTemplate(template: BaseEmailTemplate, variables: Record<string, any> = {}): Promise<{ html: string; text: string }> {
+  private async renderEmailTemplate(template: BaseEmailTemplateDocument, variables: Record<string, any> = {}): Promise<{ html: string; text: string }> {
     if (!template.content) {
       return { html: '', text: '' }
     }

src/types/index.ts

@@ -1,11 +1,44 @@
 import { Payload } from 'payload'
 import type { CollectionConfig, RichTextField } from 'payload'
 import { Transporter } from 'nodemailer'
-import {Email, EmailTemplate} from "../payload-types.js"
 
-export type BaseEmail<TEmail extends Email = Email, TEmailTemplate extends EmailTemplate = EmailTemplate> = Omit<TEmail, 'id' | 'template'> & {template: Omit<TEmailTemplate, 'id'> | TEmailTemplate['id'] | undefined | null}
+// Generic base interfaces that work with any ID type
+export interface BaseEmailDocument {
+  id: string | number
+  template?: any
+  to: string[]
+  cc?: string[]
+  bcc?: string[]
+  from?: string
+  replyTo?: string
+  subject: string
+  html: string
+  text?: string
+  variables?: Record<string, any>
+  scheduledAt?: string
+  sentAt?: string
+  status?: 'pending' | 'processing' | 'sent' | 'failed'
+  attempts?: number
+  lastAttemptAt?: string
+  error?: string
+  priority?: number
+  createdAt?: string
+  updatedAt?: string
+}
 
-export type BaseEmailTemplate<TEmailTemplate extends EmailTemplate = EmailTemplate> = Omit<TEmailTemplate, 'id'>
+export interface BaseEmailTemplateDocument {
+  id: string | number
+  name: string
+  slug: string
+  subject?: string
+  content?: any
+  createdAt?: string
+  updatedAt?: string
+}
+
+export type BaseEmail<TEmail extends BaseEmailDocument = BaseEmailDocument, TEmailTemplate extends BaseEmailTemplateDocument = BaseEmailTemplateDocument> = Omit<TEmail, 'id' | 'template'> & {template: Omit<TEmailTemplate, 'id'> | TEmailTemplate['id'] | undefined | null}
+
+export type BaseEmailTemplate<TEmailTemplate extends BaseEmailTemplateDocument = BaseEmailTemplateDocument> = Omit<TEmailTemplate, 'id'>
 
 export type TemplateRendererHook = (template: string, variables: Record<string, any>) => string | Promise<string>