Error

Introduction

The Error Handler is a global safety net for your Discord bot.

It listens to Node.js process-level errors and ensures that:

The bot does not silently crash
Errors are logged properly
Critical failures are reported to a Discord channel

This handler protects your bot from unexpected runtime crashes that normal try/catch blocks cannot catch.

Why a Global Error Handler Is Important

Some errors occur outside command execution, such as:

Unhandled promise rejections
Unexpected runtime exceptions
Internal Node.js failures

Without a global error handler:

Your bot may crash silently
Errors may go unnoticed in production

Never rely only on try/catch inside commands. Production bots must handle process-level errors.

How the Error Handler Works

The handler listens to three Node.js process events:

unhandledRejection
uncaughtException
uncaughtExceptionMonitor

Each error:

Is logged to the console
Is sent as an embed to a configured Discord channel

Requirements

Before using this handler, ensure:

ERROR_CHANNEL is set in your config
The bot has permission to send messages in that channel

ERROR_CHANNEL=123456789012345678

Full Error Handler Code

import { Client, EmbedBuilder, TextChannel } from 'discord.js'
import config from '../configs/botConfig'
import { COLORS, EMOJIS } from '../constants/botConst'

const errorHandler = (client: Client) => {
  const errorChannelId = config.ERROR_CHANNEL

  const sendErrorEmbed = async (title: string, description: string) => {
    const errorChannel = client.channels.cache.get(errorChannelId) as TextChannel

    if (!errorChannel) return

    const errorEmbed = new EmbedBuilder()
      .setTitle(title)
      .setDescription(description)
      .setColor(COLORS.red)
      .setTimestamp()

    await errorChannel.send({ embeds: [errorEmbed] })
  }

  /* ───────── Type 1: Unhandled Promise Rejection ───────── */
  process.on('unhandledRejection', (reason, promise) => {
    console.log('[ERROR-HANDLER] Unhandled Rejection')
    console.log(reason, promise)

    sendErrorEmbed(`${EMOJIS.failed} Unhandled Rejection`, `\`\`\`${String(reason)}\`\`\``)
  })

  /* ───────── Type 2: Uncaught Exception ───────── */
  process.on('uncaughtException', (error, origin) => {
    console.log('[ERROR-HANDLER] Uncaught Exception')
    console.log(error, origin)

    sendErrorEmbed(`${EMOJIS.failed} Uncaught Exception`, `\`\`\`${error}\n\n${origin}\`\`\``)
  })

  /* ───────── Type 3: Exception Monitor ───────── */
  process.on('uncaughtExceptionMonitor', (error, origin) => {
    console.log('[ERROR-HANDLER] Exception Monitor')
    console.log(error, origin)

    sendErrorEmbed(`${EMOJIS.failed} Exception Monitor`, `\`\`\`${error}\n\n${origin}\`\`\``)
  })
}

export default errorHandler

Error Types Explained

1. Unhandled Rejection

Triggered when a promise fails without .catch().

fetch(url) // no catch

Most API-related crashes come from unhandled rejections.

2. Uncaught Exception

Triggered when synchronous code throws an error outside try/catch.

throw new Error('Crash')

3. Exception Monitor

Triggered before the process crashes. Useful for last-moment logging and alerts.

Why Send Errors to Discord?

Sending errors to a Discord channel allows you to:

Monitor production issues in real time
Debug without server access
Share error logs with your team

This turns Discord into a live error dashboard.

Where to Register This Handler

Call it once, right after client creation:

import errorHandler from './handlers/errorHandler'

errorHandler(client)

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