NestJS Discord Bot

A Discord bot built with NestJS and Discord.js that echoes messages and responds to a simple /helloworld slash command.

Features

• Message Echo: Replies to user messages by appending "-bot" to the original message
• Hello World Command: Responds with "Hello World!" when users type /helloworld
• Modular Architecture: Built using NestJS's modular design patterns
• TypeScript Support: Fully typed for better developer experience

Prerequisites

• Node.js (v18 or higher)
• pnpm
• Discord account and bot token
• Discord server with admin access

Installation

1. Clone the repository:

git clone https://github.com/yourusername/discord-bot.git
cd discord-bot

2. Install dependencies:

pnpm install

3. Create a .env file in the root directory:

BOT_TOKEN=your_discord_bot_token
CLIENT_ID=your_bot_client_id

Setup Discord Bot

1. Go to the Discord Developer Portal
2. Create a new application and add bot
3. Enable the following Privileged Gateway Intents:

• Message content intent
• Server member intent

4. Copy your bot token and client ID to the .env file
5. Generate an invite URL with the following permissions:

• bot
• applications.commands
• send messages
• Read message History

6. Invite the bot to your server using the generated URL

Project Structure

src/
├── config/                 # Configuration settings
├── discord/
│   ├── commands/           # Slash command definitions
│   ├── events/             # Event handlers (messages, interactions)
│   ├── discord.module.ts   # Discord module definition
│   └── discord.service.ts  # Core Discord service
├── app.controller.ts       # Main application controller
├── app.module.ts           # Main application module
├── app.service.ts          # Application service
└── main.ts                 # Application entry point

Running the Bot

Development

# Watch mode
pnpm start:dev

Production

# Build
pnpm build

# Run in producation mode
pnpm start:prod

Testing

The project includes unit tests and integration tests for all components:

# Run all tests
pnpm test

# Run tests in watch mode
pnpm test:watch

# Generate test coverage
pnpm test:cov

Adding New Commands

1. Create a new command class in the src/discord/commands directory:

import { Injectable } from '@nestjs/common';
import { SlashCommandBuilder } from 'discord.js';
import { Command } from './command.interface';

@Injectable()
export class MyNewCommand implements Command {
  data = {
    name: 'mycommand',
    description: 'Description of my command',
    toJSON: () => {
      return new SlashCommandBuilder()
        .setName('mycommand')
        .setDescription('Description of my command')
        .toJSON();
    }
  };

  async execute(interaction) {
    await interaction.reply('This is my new command!');
  }
}

2. Register the command in discord.module.ts

@Module({
  providers: [
    // ... other providers
    MyNewCommand,
    {
      provide: 'DISCORD_COMMANDS',
      useFactory: (...commands) => commands,
      inject: [
        // ... other commands
        MyNewCommand,
      ],
    },
  ],
})

Event Handling

The bot handle two main types of events:

1. Message Create Event: Triggered when a user sends a message
2. Interaction Create Event: Triggered when a user uses a slash command

To add a new event handler, create a class in the src/discord/events directory that implements the Event interface.

Deployment

This bot can be deployed to any Node.js hosting environment. Just make sure to:

1. Set the environment variables (BOT_TOKEN, CLIENT_ID)
2. Install dependencies with pnpm install --production
3. Build the project with pnpm build
4. Start the server with pnpm start:prod

Acknowledgements

• NestJS - The progressive Node.js framework
• Discord.js - Node.js module to interact with the Discord API