@brilab-mailer/core

Overview

@brilab-mailer/core provides the foundational NestJS module responsible for:

• registering email providers
• registering template engines
• orchestrating rendering + sending
• exposing MailerService as a unified high-level interface

This is the heart of the Brilab Mailer architecture.

High-Level Architecture

                +---------------------+
                |  NestJS Application |
                +---------------------+
                           |
                           v
                +---------------------+
                |    MailerModule     |
                +---------------------+
                   |             |
                   v             v
     +-------------------+   +-------------------+
     | MailerProvider    |   | TemplateEngine    |
     +-------------------+   +-------------------+

Core Responsibilities

1. Provider Registration

You pass providerClass in MailerModule.register():

MailerModule.register({
  providerClass: MailtrapApiProvider,
});

Core will:

• instantiate the provider
• validate that it implements MailerProvider
• expose it through MAILER_PROVIDER

2. Template Engine Registration

MailerModule.register({
  templateEngineClass: HandlebarsTemplateEngine,
});

3. Unified MailerService

await this.mailer.send({
  to: email,
  subject: 'Welcome!',
  html: await this.template.render('welcome', { name }),
});

API Documentation

MailerModule.register(options)

interface MailerModuleOptions {
  providerClass: Type<MailerProvider>;
  templateEngineClass?: Type<MailerTemplateEngine>;
}

MailerService

send(options: MailerSendOptions): Promise<void>
render(template: string, context: any): Promise<string>

Error Handling Strategy

• missing provider → MailerMissingProviderException
• provider.send() error → wrapped into MailerProviderException
• missing template engine → bypass rendering (raw content)

Lifecycle

• provider instantiated once per module
• template engine instantiated once
• service stateless

Best Practices

• Always use dynamic module configuration.
• Use ConfigModule for provider secrets.
• Keep providers stateless.