Nest mailer module

A mailer module for Nest framework (node.js)

Nest MailerModule provide a wrapper around nodemailer used for send email with support for PugJS template files.

Installation

npm install --save @nest-modules/mailer

Usage

Import the MailerModule into the root ApplicationModule.

//app.module.ts
import { Module } from '@nestjs/common';
import { MailerModule } from '@nest-modules/mailer';

@Module({
  imports: [
    MailerModule.forRoot({
      transport: 'smtps://user%40domain.com:[email protected]',
      defaults: {
        from:'"nest-modules" <[email protected]>',
      },
      templateDir: './src/common/email-templates'
      templateOptions: {
        engine: 'PUG'
      }
    }),
  ],
})
export class ApplicationModule {}

The forRoot() method accepts a configuration JSON object with the following attributes:

transport is the transport configuration object, connection url or a transport plugin instance

defaults is an optional object of message data fields that are set for every message sent

templateDir is the path to directory where you have put your templates; the default value is /public/templates if not specified.

templateOptions.engine is the template engine used for rendering html. Accepts PUG (default) or HANDLEBARS (case-insensitive).

templateOptions.precompiledTemplates is a hash of templateName: (context) => htmlString. Currently only used in handlebars engine, to optimize dynamic rendering.

templateOptions.engineAdapter is a custom templating function. The function signature is (templateDir: string, mail: any, callback: (err?: any, data?: string) => any).

For more details about transporters and defaults values please visit: nodemailer

Futhermore, instead of passing anything to the forRoot(), we can create an mailerconfig.ts file in the project root directory.

//mailerconfig.ts
export = {
  transport: {
    host: 'smtp.example.com',
    port: 587,
    secure: false,
    auth: {
      user: 'username',
      pass: 'password'
    }
  },
  defaults: {
    forceEmbeddedImages: true,
    from:'"nest-modules" <[email protected]>',
  },
  templateDir: './src/common/email-templates'
}

Now we can simply leave the parenthesis empty:

//app.module.ts
app.module.ts JavaScript TypeScript

import { Module } from '@nestjs/common';
import { MailerModule } from '@nest-modules/mailer';

@Module({
  imports: [MailerModule.forRoot()],
})
export class ApplicationModule {}

Afterwards, MailerProvider will be available to inject across entire project (without importing any module elsewhere), for example in this way:

@Inject('MailerProvider') private readonly mailerProvider

Async configuration

Quite often you might want to asynchronously pass your module options instead of passing them beforehand. In such case, use forRootAsync() method, that provides a couple of various ways to deal with async data.

useFactory:

First possible approach is to use a factory function. Our factory behaves like every other one (might be async and is able to inject dependencies through inject):

MailerModule.forRootAsync({
 imports: [ConfigModule],
  useFactory: async (config: ConfigService) => ({
    transport: config.getString('MAILER_TRANSPORT'),
    ...
  }),
  inject: [ConfigService],
})

useClass:

Alternatively, you are able to use class instead of a factory.

MailerModule.forRootAsync({
  useClass: MailerConfigService,
})

Above construction will instantiate MailerConfigService inside MailerModule and will leverage it to create options object. The MailerConfigService has to implement MailerOptionsFactory interface.

@Injectable()
export class MailerConfigService implements MailerOptionsFactory {
  constructor(
    private readonly config: ConfigService
  ){}
  createMailerOptions(): MailerModuleOptions {
    return {
      transport: this.config.getString('MAILER_TRANSPORT'),
      ...
    };
  }
}

Sending messages:

MailerProvider exports the sendMail() function to which you can pass the message options (sender, email subject, recipient, body content, etc)

sendMail() acept the same fields of an nodemailer email message

ex:

this.mailerProvider.sendMail({
  to: '[email protected]', // sender address
  from: '[email protected]', // list of receivers
  subject: 'Testing Nest MailerModule ✔', // Subject line
  text: 'welcome', // plaintext body
  html: '<b>welcome</b>' // HTML body content
})

This method returns a Promise object

Templating:

MailerModule renders pug/handlebars templates using the data specified in the context message object

ex:

this.mailerProvider.sendMail({
  to: '[email protected]',
  from: '[email protected]',
  subject: 'Testing Nest Mailermodule with template ✔',
  template: 'welcome', // The `.pug` or `.hbs` extension is appended automatically.
  context: {  // Data to be sent to template engine.
    username: 'john doe',
    code: 'cf1a3f828287'
  }
})

where:

template is a name from template file (without extension)

context is an object with dynamic content which will be bing to templates

Pug engine:

Create a pug template in your templateDir, on this case:

<templateDir>/welcome.pug

Put this code in your template:

p Welcome #{username}, your activation code is #{code}

Pug will compile the template to html code and return the body of message

The result is:

<p>Welcome john doe, your activation code is cf1a3f828287</p>

Handlebars engine:

Or for handlebars create a template

<templateDir>/welcome.hbs

With the following content

<h1>Welcome {{username}}!</h1>
<p>your activation code is {{code}}</p>

and set the templateOptions.engine parameter to handlebars (case-insensitive):

export = {
  transport: 'smtps://user%40domain.com:[email protected]',
  defaults: {
    forceEmbeddedImages: true,
    from:'"nest-modules" <[email protected]>',
  },
  templateDir: './src/common/email-templates',
  templateOptions: {
    engine: 'handlebars'
  }
}

You can also supply precompiled templates, for instance in handlebars:

export = {
  transport: 'smtps://user%40domain.com:[email protected]',
  defaults: {
    forceEmbeddedImages: true,
    from: '"nest-modules" <[email protected]>',
  },
  templateDir: './src/common/email-templates',
  templateOptions: {
    precompiledTemplates: {
      test_1: Handlebars.compile(test_1_string),
      test_2: Handlebars.compile(test_2_string)
    },
    engine: 'handlebars',
  },
};

Custom template Adaptor

Pug and Handlebars are natively supported (via the templateOptions.engine option), but you can pass in a custom template adaptor function (such as EJS) to the templateOptions.adaptor config:

const customAdaptor = (templateDir, mail, callback) => {
  const templatePath = path.join(process.cwd(), templateDir, mail.data.template) + '.html';

  try {
    const templateString = fs.readFileSync(templatePath, 'UTF-8');
    mail.data.html = templateString.replace(/javascript/g, 'typescript');
    return callback();
  } catch (err) {
    return callback(err);
  }
}

export = {
  transport: 'smtps://user%40domain.com:[email protected]',
  defaults: {
    forceEmbeddedImages: true,
    from:'"nest-modules" <[email protected]>',
  },
  templateDir: './src/common/email-templates',
  templateOptions: {
    engineAdapter: customAdaptor
  }
}

Using a transport plugin instance:

In some cases you will want to use a nodemailer transport plugin, such as mandrill, sendgrid, mailgun, etc.

You must only create the instance and send it to the transport value.

ex:

npm install --save nodemailer-mandrill-transport

import * as mandrillTransport from 'nodemailer-mandrill-transport'

export = {
  transport: mandrillTransport({
    auth: {
      api_key: 'key'
    }
  }),
  defaults: {
    from:'"nest-mailer" <[email protected]>',
  },
  templateDir: './src/common/email-templates'
}

Contributing

• Paweł Partyka
• Cristiam Diaz
• Pat McGowan

License

MIT