Merge pull request #16 from xtr-dev/dev

Replace Handlebars with flexible template engine system

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@xtr-dev/payload-mailing",
-  "version": "0.0.4",
+  "version": "0.0.12",
   "description": "Template-based email system with scheduling and job processing for PayloadCMS",
   "type": "module",
   "main": "dist/index.js",
@@ -47,9 +47,12 @@
     "payload": "^3.37.0"
   },
   "dependencies": {
-    "handlebars": "^4.7.8",
     "nodemailer": "^6.9.8"
   },
+  "optionalDependencies": {
+    "liquidjs": "^10.19.0",
+    "mustache": "^4.2.0"
+  },
   "devDependencies": {
     "@eslint/eslintrc": "^3.2.0",
     "@payloadcms/db-mongodb": "^3.37.0",

pnpm-lock.yaml

@@ -8,9 +8,6 @@ importers:
 
   .:
     dependencies:
-      handlebars:
-        specifier: ^4.7.8
-        version: 4.7.8
       nodemailer:
         specifier: ^6.9.8
         version: 6.10.1
@@ -117,6 +114,13 @@ importers:
       vitest:
         specifier: ^3.1.2
         version: 3.2.4(@types/debug@4.1.12)(@types/node@22.18.1)(sass@1.77.4)(tsx@4.20.3)
+    optionalDependencies:
+      liquidjs:
+        specifier: ^10.19.0
+        version: 10.21.1
+      mustache:
+        specifier: ^4.2.0
+        version: 4.2.0
 
 packages:
 
@@ -2637,6 +2641,10 @@ packages:
   colorette@2.0.20:
     resolution: {integrity: sha512-IfEDxwoWIjkeXL1eXcDiow4UbKjhLdq6/EuSVR9GMN7KVH3r9gQ83e73hsz1Nd1T3ijd5xv1wcWRYO+D6kCI2w==}
 
+  commander@10.0.1:
+    resolution: {integrity: sha512-y4Mg2tXshplEbSGzx7amzPwKKOCGuoSRP/CjEdwwk0FOGlUbq6lKuoyDZTNZkmxHdJtp54hdfY/JUrdL7Xfdug==}
+    engines: {node: '>=14'}
+
   commander@2.20.3:
     resolution: {integrity: sha512-GpVkmM8vF2vQUkj2LvZmD35JxeJOLCwJ9cUkugyk2nuhbv3+mJvpLYYt+0+USMxE+oj+ey/lJEnhZw75x/OMcQ==}
 
@@ -3540,11 +3548,6 @@ packages:
     resolution: {integrity: sha512-mS1lbMsxgQj6hge1XZ6p7GPhbrtFwUFYi3wRzXAC/FmYnyXMTvvI3td3rjmQ2u8ewXueaSvRPWaEcgVVOT9Jnw==}
     engines: {node: ^12.22.0 || ^14.16.0 || ^16.0.0 || >=17.0.0}
 
-  handlebars@4.7.8:
-    resolution: {integrity: sha512-vafaFqs8MZkRrSX7sFVUdo3ap/eNiLnb4IakshzvP56X5Nr1iGKAIqdX6tMlm6HcNRIkr6AxO5jFEoJzzpT8aQ==}
-    engines: {node: '>=0.4.7'}
-    hasBin: true
-
   has-bigints@1.1.0:
     resolution: {integrity: sha512-R3pbpkcIqv2Pm3dUwgjclDRVmWpTJW2DcMzcIhEXEx1oh/CEMObMm3KLmRJOdvhM7o4uQBnwr8pzRK2sJWIqfg==}
     engines: {node: '>= 0.4'}
@@ -3922,6 +3925,11 @@ packages:
   lines-and-columns@1.2.4:
     resolution: {integrity: sha512-7ylylesZQ/PV29jhEDl3Ufjo6ZX7gCqJr5F7PKrqc93v7fzSymt1BpwEU8nAUXs8qzzvqhbjhK5QZg6Mt/HkBg==}
 
+  liquidjs@10.21.1:
+    resolution: {integrity: sha512-NZXmCwv3RG5nire3fmIn9HsOyJX3vo+ptp0yaXUHAMzSNBhx74Hm+dAGJvscUA6lNqbLuYfXgNavRQ9UbUJhQQ==}
+    engines: {node: '>=14'}
+    hasBin: true
+
   locate-path@5.0.0:
     resolution: {integrity: sha512-t7hw9pI+WvuwNJXwk5zVHpyhIqzg2qTlklJOf0mVxGSbe3Fp2VieZcduNYjaLDoy6p9uGpQEGWG87WpMKlNq8g==}
     engines: {node: '>=8'}
@@ -4186,6 +4194,10 @@ packages:
   ms@2.1.3:
     resolution: {integrity: sha512-6FlzubTLZG3J2a/NVCAleEhjzq5oxgHyaCU9yYXvcLsvoVaHJq/s5xXI6/XXP6tz7R9xAOtHnSO/tXtF3WRTlA==}
 
+  mustache@4.2.0:
+    resolution: {integrity: sha512-71ippSywq5Yb7/tVYyGbkBggbU8H3u5Rz56fH60jGFgr8uHwxs+aSKeqmluIVzM0m0kB7xQjKS6qPfd0b2ZoqQ==}
+    hasBin: true
+
   nanoid@3.3.11:
     resolution: {integrity: sha512-N8SpfPUnUp1bK+PMYW8qSWdl9U+wwNWI4QKxOYDy9JAro3WMX7p2OeVRF9v+347pnakNevPmiHhNmZ2HbFA76w==}
     engines: {node: ^10 || ^12 || ^13.7 || ^14 || >=15.0.1}
@@ -4202,9 +4214,6 @@ packages:
   natural-compare@1.4.0:
     resolution: {integrity: sha512-OWND8ei3VtNC9h7V60qff3SVobHr996CTwgxubgyQYEpg290h9J0buyECNNJexkFm5sOajh5G116RYA1c8ZMSw==}
 
-  neo-async@2.6.2:
-    resolution: {integrity: sha512-Yd3UES5mWCSqR+qNT93S3UoYUkqAZ9lLg8a7g9rimsWmYGK8cVToA4/sF3RrshdyV3sAGMXVUmpMYOw+dLpOuw==}
-
   new-find-package-json@2.0.0:
     resolution: {integrity: sha512-lDcBsjBSMlj3LXH2v/FW3txlh2pYTjmbOXPYJD93HI5EwuLzI11tdHSIpUMmfq/IOsldj4Ps8M8flhm+pCK4Ew==}
     engines: {node: '>=12.22.0'}
@@ -5170,11 +5179,6 @@ packages:
     engines: {node: '>=14.17'}
     hasBin: true
 
-  uglify-js@3.19.3:
-    resolution: {integrity: sha512-v3Xu+yuwBXisp6QYTcH4UbH+xYJXqnq2m/LtQVWKWzYc1iehYnLixoQDN9FH6/j9/oybfd6W9Ghwkl8+UMKTKQ==}
-    engines: {node: '>=0.8.0'}
-    hasBin: true
-
   uint8array-extras@1.5.0:
     resolution: {integrity: sha512-rvKSBiC5zqCCiDZ9kAOszZcDvdAHwwIKJG33Ykj43OKcWsnmcBRL09YTU4nOeHZ8Y2a7l1MgTd08SBe9A8Qj6A==}
     engines: {node: '>=18'}
@@ -5377,9 +5381,6 @@ packages:
     resolution: {integrity: sha512-BN22B5eaMMI9UMtjrGd5g5eCYPpCPDUy0FJXbYsaT5zYxjFOckS53SQDE3pWkVoWpHXVb3BrYcEN4Twa55B5cA==}
     engines: {node: '>=0.10.0'}
 
-  wordwrap@1.0.0:
-    resolution: {integrity: sha512-gvVzJFlPycKc5dZN4yPkP8w7Dc37BtP1yczEneOb4uq34pXZcvrtRTmWV8W+Ume+XCxKgbjM+nevkyFPMybd4Q==}
-
   wrap-ansi@7.0.0:
     resolution: {integrity: sha512-YVGIj2kamLSTxw6NsZjoBxfSwsn0ycdesmc4p+Q21c5zPuZ1pl+NfxVdxPtdHvmNVOQ6XSYG4AUtyt/Fi7D16Q==}
     engines: {node: '>=10'}
@@ -8540,6 +8541,9 @@ snapshots:
 
   colorette@2.0.20: {}
 
+  commander@10.0.1:
+    optional: true
+
   commander@2.20.3: {}
 
   commander@6.2.1: {}
@@ -9689,15 +9693,6 @@ snapshots:
 
   graphql@16.11.0: {}
 
-  handlebars@4.7.8:
-    dependencies:
-      minimist: 1.2.8
-      neo-async: 2.6.2
-      source-map: 0.6.1
-      wordwrap: 1.0.0
-    optionalDependencies:
-      uglify-js: 3.19.3
-
   has-bigints@1.1.0: {}
 
   has-flag@4.0.0: {}
@@ -10044,6 +10039,11 @@ snapshots:
 
   lines-and-columns@1.2.4: {}
 
+  liquidjs@10.21.1:
+    dependencies:
+      commander: 10.0.1
+    optional: true
+
   locate-path@5.0.0:
     dependencies:
       p-locate: 4.1.0
@@ -10431,6 +10431,9 @@ snapshots:
 
   ms@2.1.3: {}
 
+  mustache@4.2.0:
+    optional: true
+
   nanoid@3.3.11: {}
 
   napi-postinstall@0.3.3: {}
@@ -10439,8 +10442,6 @@ snapshots:
 
   natural-compare@1.4.0: {}
 
-  neo-async@2.6.2: {}
-
   new-find-package-json@2.0.0:
     dependencies:
       debug: 4.4.1
@@ -11571,9 +11572,6 @@ snapshots:
 
   typescript@5.9.2: {}
 
-  uglify-js@3.19.3:
-    optional: true
-
   uint8array-extras@1.5.0: {}
 
   unbox-primitive@1.1.0:
@@ -11820,8 +11818,6 @@ snapshots:
 
   word-wrap@1.2.5: {}
 
-  wordwrap@1.0.0: {}
-
   wrap-ansi@7.0.0:
     dependencies:
       ansi-styles: 4.3.0

src/plugin.ts

@@ -4,9 +4,61 @@ import { MailingService } from './services/MailingService.js'
 import { createEmailTemplatesCollection } from './collections/EmailTemplates.js'
 import Emails from './collections/Emails.js'
 
+// Helper function to schedule the email processing job
+async function scheduleEmailProcessingJob(payload: any, queueName: string, delayMs: number = 60000): Promise<boolean> {
+  if (!queueName || typeof queueName !== 'string') {
+    throw new Error('Invalid queueName: must be a non-empty string')
+  }
+
+  const jobSlug = 'process-email-queue'
+
+  // Check if there's already a scheduled job for this task
+  const existingJobs = await payload.find({
+    collection: 'payload-jobs',
+    where: {
+      and: [
+        {
+          taskSlug: {
+            equals: jobSlug,
+          },
+        },
+        {
+          hasCompleted: {
+            equals: false,
+          },
+        },
+      ],
+    },
+    limit: 1,
+  })
+
+  // If no existing job, schedule a new one
+  if (existingJobs.docs.length === 0) {
+    await payload.create({
+      collection: 'payload-jobs',
+      data: {
+        taskSlug: jobSlug,
+        input: {},
+        queue: queueName,
+        waitUntil: new Date(Date.now() + delayMs),
+      },
+    })
+    console.log(`🔄 Scheduled email processing job in queue: ${queueName}`)
+    return true
+  } else {
+    console.log(`✅ Email processing job already scheduled in queue: ${queueName}`)
+    return false
+  }
+}
+
 export const mailingPlugin = (pluginConfig: MailingPluginConfig) => (config: Config): Config => {
   const queueName = pluginConfig.queue || 'default'
 
+  // Validate queueName
+  if (!queueName || typeof queueName !== 'string') {
+    throw new Error('Invalid queue configuration: queue must be a non-empty string')
+  }
+
   // Handle templates collection configuration
   const templatesConfig = pluginConfig.collections?.templates
   const templatesSlug = typeof templatesConfig === 'string' ? templatesConfig : 'email-templates'
@@ -80,8 +132,11 @@ export const mailingPlugin = (pluginConfig: MailingPluginConfig) => (config: Con
         {
           slug: 'process-email-queue',
           handler: async ({ job, req }: { job: any; req: any }) => {
+            const payload = (req as any).payload
+            let jobResult = null
+
             try {
-              const mailingService = new MailingService((req as any).payload, pluginConfig)
+              const mailingService = new MailingService(payload, pluginConfig)
 
               console.log('🔄 Processing email queue (pending + failed emails)...')
 
@@ -91,19 +146,41 @@ export const mailingPlugin = (pluginConfig: MailingPluginConfig) => (config: Con
               // Then retry failed emails
               await mailingService.retryFailedEmails()
 
-              return {
+              jobResult = {
                 output: {
                   success: true,
                   message: 'Email queue processed successfully (pending and failed emails)'
                 }
               }
+
+              console.log('✅ Email queue processing completed successfully')
+
             } catch (error) {
               console.error('❌ Error processing email queue:', error)
               const errorMessage = error instanceof Error ? error.message : 'Unknown error'
 
-              // Properly fail the job by throwing the error
-              throw new Error(`Email queue processing failed: ${errorMessage}`)
+              jobResult = new Error(`Email queue processing failed: ${errorMessage}`)
             }
+
+            // Always reschedule the next job (success or failure) using duplicate prevention
+            let rescheduled = false
+            try {
+              rescheduled = await scheduleEmailProcessingJob(payload, queueName, 300000) // Reschedule in 5 minutes
+              if (rescheduled) {
+                console.log(`🔄 Rescheduled next email processing job in ${queueName} queue`)
+              }
+            } catch (rescheduleError) {
+              console.error('❌ Failed to reschedule email processing job:', rescheduleError)
+              // If rescheduling fails, we should warn but not fail the current job
+              // since the email processing itself may have succeeded
+              console.warn('⚠️  Email processing completed but next job could not be scheduled')
+            }
+
+            // Return the original result or throw the error
+            if (jobResult instanceof Error) {
+              throw jobResult
+            }
+            return jobResult
           },
           interfaceName: 'ProcessEmailQueueJob',
         },
@@ -130,6 +207,13 @@ export const mailingPlugin = (pluginConfig: MailingPluginConfig) => (config: Con
 
       console.log('PayloadCMS Mailing Plugin initialized successfully')
 
+      // Schedule the email processing job if not already scheduled
+      try {
+        await scheduleEmailProcessingJob(payload, queueName)
+      } catch (error) {
+        console.error('Failed to schedule email processing job:', error)
+      }
+
       // Call onReady callback if provided
       if (pluginConfig.onReady) {
         await pluginConfig.onReady(payload)

src/services/MailingService.ts

@@ -1,9 +1,9 @@
 import { Payload } from 'payload'
-import Handlebars from 'handlebars'
+import { Liquid } from 'liquidjs'
 import nodemailer, { Transporter } from 'nodemailer'
-import { 
-  MailingPluginConfig, 
-  SendEmailOptions, 
+import {
+  MailingPluginConfig,
+  SendEmailOptions,
   MailingService as IMailingService,
   EmailTemplate,
   QueuedEmail,
@@ -15,22 +15,22 @@ import { serializeRichTextToHTML, serializeRichTextToText } from '../utils/richT
 export class MailingService implements IMailingService {
   private payload: Payload
   private config: MailingPluginConfig
-  private transporter!: Transporter
+  private transporter!: Transporter | any
   private templatesCollection: string
   private emailsCollection: string
+  private liquid: Liquid | null | false = null
 
   constructor(payload: Payload, config: MailingPluginConfig) {
     this.payload = payload
     this.config = config
-    
+
     const templatesConfig = config.collections?.templates
     this.templatesCollection = typeof templatesConfig === 'string' ? templatesConfig : 'email-templates'
-    
+
     const emailsConfig = config.collections?.emails
     this.emailsCollection = typeof emailsConfig === 'string' ? emailsConfig : 'emails'
-    
+
     this.initializeTransporter()
-    this.registerHandlebarsHelpers()
   }
 
   private initializeTransporter(): void {
@@ -40,44 +40,71 @@ export class MailingService implements IMailingService {
       } else {
         this.transporter = nodemailer.createTransport(this.config.transport as MailingTransportConfig)
       }
+    } else if (this.payload.email && 'sendMail' in this.payload.email) {
+      // Use Payload's configured mailer (cast to any to handle different adapter types)
+      this.transporter = this.payload.email as any
     } else {
-      throw new Error('Email transport configuration is required')
+      throw new Error('Email transport configuration is required either in plugin config or Payload config')
     }
   }
 
-  private registerHandlebarsHelpers(): void {
-    Handlebars.registerHelper('formatDate', (date: Date, format?: string) => {
-      if (!date) return ''
-      const d = new Date(date)
-      if (format === 'short') {
-        return d.toLocaleDateString()
-      }
-      if (format === 'long') {
-        return d.toLocaleDateString('en-US', { 
-          year: 'numeric', 
-          month: 'long', 
-          day: 'numeric' 
+  private getDefaultFrom(): string {
+    const fromEmail = this.config.defaultFrom
+    const fromName = this.config.defaultFromName
+
+    // Check if fromName exists, is not empty after trimming, and fromEmail exists
+    if (fromName && fromName.trim() && fromEmail) {
+      // Escape quotes in the display name to prevent malformed headers
+      const escapedName = fromName.replace(/"/g, '\\"')
+      return `"${escapedName}" <${fromEmail}>`
+    }
+
+    return fromEmail || ''
+  }
+
+  private async ensureLiquidJSInitialized(): Promise<void> {
+    if (this.liquid !== null) return // Already initialized or failed
+
+    try {
+      const liquidModule = await import('liquidjs')
+      const { Liquid: LiquidEngine } = liquidModule
+      this.liquid = new LiquidEngine()
+
+      // Register custom filters (equivalent to Handlebars helpers)
+      if (this.liquid && typeof this.liquid !== 'boolean') {
+        this.liquid.registerFilter('formatDate', (date: any, format?: string) => {
+          if (!date) return ''
+          const d = new Date(date)
+          if (format === 'short') {
+            return d.toLocaleDateString()
+          }
+          if (format === 'long') {
+            return d.toLocaleDateString('en-US', {
+              year: 'numeric',
+              month: 'long',
+              day: 'numeric'
+            })
+          }
+          return d.toLocaleString()
+        })
+
+        this.liquid.registerFilter('formatCurrency', (amount: any, currency = 'USD') => {
+          if (typeof amount !== 'number') return amount
+          return new Intl.NumberFormat('en-US', {
+            style: 'currency',
+            currency: currency
+          }).format(amount)
+        })
+
+        this.liquid.registerFilter('capitalize', (str: any) => {
+          if (typeof str !== 'string') return str
+          return str.charAt(0).toUpperCase() + str.slice(1)
         })
       }
-      return d.toLocaleString()
-    })
-
-    Handlebars.registerHelper('formatCurrency', (amount: number, currency = 'USD') => {
-      if (typeof amount !== 'number') return amount
-      return new Intl.NumberFormat('en-US', {
-        style: 'currency',
-        currency: currency
-      }).format(amount)
-    })
-
-    Handlebars.registerHelper('ifEquals', function(this: any, arg1: any, arg2: any, options: any) {
-      return (arg1 === arg2) ? options.fn(this) : options.inverse(this)
-    })
-
-    Handlebars.registerHelper('capitalize', (str: string) => {
-      if (typeof str !== 'string') return str
-      return str.charAt(0).toUpperCase() + str.slice(1)
-    })
+    } catch (error) {
+      console.warn('LiquidJS not available. Falling back to simple variable replacement. Install liquidjs or use a different templateEngine.')
+      this.liquid = false // Mark as failed to avoid retries
+    }
   }
 
   async sendEmail(options: SendEmailOptions): Promise<string> {
@@ -87,7 +114,7 @@ export class MailingService implements IMailingService {
     })
 
     await this.processEmailItem(emailId)
-    
+
     return emailId
   }
 
@@ -99,14 +126,14 @@ export class MailingService implements IMailingService {
 
     if (options.templateSlug) {
       const template = await this.getTemplateBySlug(options.templateSlug)
-      
+
       if (template) {
         templateId = template.id
         const variables = options.variables || {}
         const renderedContent = await this.renderEmailTemplate(template, variables)
         html = renderedContent.html
         text = renderedContent.text
-        subject = this.renderHandlebarsTemplate(template.subject, variables)
+        subject = await this.renderTemplate(template.subject, variables)
       } else {
         throw new Error(`Email template not found: ${options.templateSlug}`)
       }
@@ -125,7 +152,7 @@ export class MailingService implements IMailingService {
       to: Array.isArray(options.to) ? options.to : [options.to],
       cc: options.cc ? (Array.isArray(options.cc) ? options.cc : [options.cc]) : undefined,
       bcc: options.bcc ? (Array.isArray(options.bcc) ? options.bcc : [options.bcc]) : undefined,
-      from: options.from || this.config.defaultFrom,
+      from: options.from || this.getDefaultFrom(),
       replyTo: options.replyTo,
       subject: subject || options.subject,
       html,
@@ -147,7 +174,7 @@ export class MailingService implements IMailingService {
 
   async processEmails(): Promise<void> {
     const currentTime = new Date().toISOString()
-    
+
     const { docs: pendingEmails } = await this.payload.find({
       collection: this.emailsCollection as any,
       where: {
@@ -242,7 +269,7 @@ export class MailingService implements IMailingService {
       }) as QueuedEmail
 
       let emailObject: EmailObject = {
-        from: email.from || this.config.defaultFrom,
+        from: email.from || this.getDefaultFrom(),
         to: email.to,
         cc: email.cc || undefined,
         bcc: email.bcc || undefined,
@@ -259,7 +286,7 @@ export class MailingService implements IMailingService {
       }
 
       const mailOptions = {
-        from: emailObject.from || this.config.defaultFrom,
+        from: emailObject.from,
         to: emailObject.to,
         cc: emailObject.cc || undefined,
         bcc: emailObject.bcc || undefined,
@@ -331,7 +358,7 @@ export class MailingService implements IMailingService {
         },
         limit: 1,
       })
-      
+
       return docs.length > 0 ? docs[0] as EmailTemplate : null
     } catch (error) {
       console.error(`Template with slug '${templateSlug}' not found:`, error)
@@ -339,14 +366,62 @@ export class MailingService implements IMailingService {
     }
   }
 
-  private renderHandlebarsTemplate(template: string, variables: Record<string, any>): string {
-    try {
-      const compiled = Handlebars.compile(template)
-      return compiled(variables)
-    } catch (error) {
-      console.error('Handlebars template rendering error:', error)
-      return template
+  private async renderTemplate(template: string, variables: Record<string, any>): Promise<string> {
+    // Use custom template renderer if provided
+    if (this.config.templateRenderer) {
+      try {
+        return await this.config.templateRenderer(template, variables)
+      } catch (error) {
+        console.error('Custom template renderer error:', error)
+        return template
+      }
     }
+
+    const engine = this.config.templateEngine || 'liquidjs'
+
+    // Use LiquidJS if configured
+    if (engine === 'liquidjs') {
+      try {
+        await this.ensureLiquidJSInitialized()
+        if (this.liquid && typeof this.liquid !== 'boolean') {
+          return await this.liquid.parseAndRender(template, variables)
+        }
+      } catch (error) {
+        console.error('LiquidJS template rendering error:', error)
+      }
+    }
+
+    // Use Mustache if configured
+    if (engine === 'mustache') {
+      try {
+        const mustacheResult = await this.renderWithMustache(template, variables)
+        if (mustacheResult !== null) {
+          return mustacheResult
+        }
+      } catch (error) {
+        console.warn('Mustache not available. Falling back to simple variable replacement. Install mustache package.')
+      }
+    }
+
+    // Fallback to simple variable replacement
+    return this.simpleVariableReplacement(template, variables)
+  }
+
+  private async renderWithMustache(template: string, variables: Record<string, any>): Promise<string | null> {
+    try {
+      const mustacheModule = await import('mustache')
+      const Mustache = mustacheModule.default || mustacheModule
+      return Mustache.render(template, variables)
+    } catch (error) {
+      return null
+    }
+  }
+
+  private simpleVariableReplacement(template: string, variables: Record<string, any>): string {
+    return template.replace(/\{\{(\w+)\}\}/g, (match, key) => {
+      const value = variables[key]
+      return value !== undefined ? String(value) : match
+    })
   }
 
   private async renderEmailTemplate(template: EmailTemplate, variables: Record<string, any> = {}): Promise<{ html: string; text: string }> {
@@ -358,11 +433,11 @@ export class MailingService implements IMailingService {
     let html = serializeRichTextToHTML(template.content)
     let text = serializeRichTextToText(template.content)
 
-    // Apply Handlebars variables to the rendered content
-    html = this.renderHandlebarsTemplate(html, variables)
-    text = this.renderHandlebarsTemplate(text, variables)
+    // Apply template variables to the rendered content
+    html = await this.renderTemplate(html, variables)
+    text = await this.renderTemplate(text, variables)
 
     return { html, text }
   }
 
-}
+}

src/types/index.ts

@@ -16,17 +16,24 @@ export interface EmailObject {
 
 export type EmailWrapperHook = (email: EmailObject) => EmailObject | Promise<EmailObject>
 
+export type TemplateRendererHook = (template: string, variables: Record<string, any>) => string | Promise<string>
+
+export type TemplateEngine = 'liquidjs' | 'mustache' | 'simple'
+
 export interface MailingPluginConfig {
   collections?: {
     templates?: string | Partial<CollectionConfig>
     emails?: string | Partial<CollectionConfig>
   }
   defaultFrom?: string
+  defaultFromName?: string
   transport?: Transporter | MailingTransportConfig
   queue?: string
   retryAttempts?: number
   retryDelay?: number
   emailWrapper?: EmailWrapperHook
+  templateRenderer?: TemplateRendererHook
+  templateEngine?: TemplateEngine
   richTextEditor?: RichTextField['editor']
   onReady?: (payload: any) => Promise<void>
   initOrder?: 'before' | 'after'

src/types/mustache.d.ts

@@ -0,0 +1,7 @@
+declare module 'mustache' {
+  interface MustacheStatic {
+    render(template: string, view?: any, partials?: any, tags?: string[]): string
+  }
+  const mustache: MustacheStatic
+  export = mustache
+}

template-syntax-migration.md

@@ -0,0 +1,160 @@
+# Template Engine Options
+
+The plugin now supports flexible template rendering with multiple options:
+
+1. **String-based Configuration** (easy setup with built-in engines)
+2. **Custom Template Renderer Hook** (maximum flexibility)
+3. **Simple Variable Replacement** (fallback, no dependencies)
+
+## Configuration Options
+
+### String-based Template Engine Configuration
+Easy setup using built-in template engines:
+
+```typescript
+// Using LiquidJS (default, requires: npm install liquidjs)
+mailingPlugin({
+  templateEngine: 'liquidjs'
+})
+
+// Using Mustache (requires: npm install mustache)
+mailingPlugin({
+  templateEngine: 'mustache'
+})
+
+// Using simple variable replacement (no dependencies)
+mailingPlugin({
+  templateEngine: 'simple'
+})
+```
+
+### Custom Template Renderer Hook
+```typescript
+// Example with Handlebars
+import Handlebars from 'handlebars'
+
+mailingPlugin({
+  templateRenderer: async (template: string, variables: Record<string, any>) => {
+    const compiled = Handlebars.compile(template)
+    return compiled(variables)
+  }
+})
+
+// Example with Mustache
+import Mustache from 'mustache'
+
+mailingPlugin({
+  templateRenderer: async (template: string, variables: Record<string, any>) => {
+    return Mustache.render(template, variables)
+  }
+})
+
+// Example with Nunjucks
+import nunjucks from 'nunjucks'
+
+mailingPlugin({
+  templateRenderer: async (template: string, variables: Record<string, any>) => {
+    return nunjucks.renderString(template, variables)
+  }
+})
+```
+
+### Using LiquidJS (Optional)
+Install the optional dependency:
+```bash
+npm install liquidjs
+# or
+pnpm add liquidjs
+```
+
+### Fallback Mode
+If no custom renderer is provided and neither LiquidJS nor Mustache are installed, simple `{{variable}}` replacement is used.
+
+## Template Syntax Reference
+
+### Mustache Syntax (Logic-less)
+```mustache
+Hello {{user.name}},
+
+{{#user.isPremium}}
+  Welcome to premium! Your balance is {{balance}}.
+{{/user.isPremium}}
+
+{{#orders}}
+  Order: {{id}} - {{date}}
+{{/orders}}
+```
+
+### LiquidJS Syntax (With Logic)
+```liquid
+Hello {{user.name}},
+
+{% if user.isPremium %}
+  Welcome to premium! Your balance is {{balance | formatCurrency}}.
+{% endif %}
+
+{% for order in orders %}
+  Order: {{order.id}} - {{order.date | formatDate: "short"}}
+{% endfor %}
+```
+
+### Simple Variable Replacement
+```
+Hello {{user.name}},
+Your balance is {{balance}}.
+```
+
+## Migration from Handlebars
+
+### Variables
+- **Handlebars**: `{{variable}}`
+- **LiquidJS**: `{{variable}}` (same)
+
+### Conditionals
+- **Handlebars**: `{{#if condition}}content{{/if}}`
+- **LiquidJS**: `{% if condition %}content{% endif %}`
+
+### Loops
+- **Handlebars**: `{{#each items}}{{this}}{{/each}}`
+- **LiquidJS**: `{% for item in items %}{{item}}{% endfor %}`
+
+### Filters/Helpers
+- **Handlebars**: `{{formatDate date "short"}}`
+- **LiquidJS**: `{{date | formatDate: "short"}}`
+
+### Available Filters
+- `formatDate` - Format dates (short, long, or default)
+- `formatCurrency` - Format currency amounts
+- `capitalize` - Capitalize first letter
+
+### Comparison Operations (LiquidJS Advantage)
+- **Handlebars**: Required `{{#ifEquals}}` helper
+- **LiquidJS**: Built-in: `{% if user.role == "admin" %}`
+
+## Example Migration
+
+### Before (Handlebars)
+```handlebars
+Hello {{user.name}},
+
+{{#if user.isPremium}}
+  Welcome to premium! Your balance is {{formatCurrency balance}}.
+{{/if}}
+
+{{#each orders}}
+  Order: {{this.id}} - {{formatDate this.date "short"}}
+{{/each}}
+```
+
+### After (LiquidJS)
+```liquid
+Hello {{user.name}},
+
+{% if user.isPremium %}
+  Welcome to premium! Your balance is {{balance | formatCurrency}}.
+{% endif %}
+
+{% for order in orders %}
+  Order: {{order.id}} - {{order.date | formatDate: "short"}}
+{% endfor %}
+```