Custom Logger

Seyfert provides a built-in Logger class that can be customized to fit your needs.

Logger.customize()

Override the default log format:

import { Logger } from 'seyfert';

Logger.customize((logger, level, args) => {
    const timestamp = new Date().toISOString();
    const mem = (process.memoryUsage().heapUsed / 1024 / 1024).toFixed(1);
    return [`[${timestamp}]`, `[${mem}MB]`, `${logger.name ?? ''} >`, ...args];
});

File-Based Logging

Enable writing logs to files:

import { Logger } from 'seyfert';

// Log everything to files
Logger.saveOnFile = 'all';

// Or only log selected logger names to files
Logger.saveOnFile = ['[Seyfert]'];

// Set the directory for log files
Logger.dirname = 'logs';

Custom Logger Methods

Extend the Logger prototype to add custom methods:

import { Logger } from 'seyfert';
import { LogLevels } from 'seyfert/lib/common';

Logger.prototype.success = function (...args: unknown[]) {
    this.rawLog(LogLevels.Info, ...args);
};

Logger.prototype.cmd = function (...args: unknown[]) {
    this.rawLog(LogLevels.Info, ...args);
};

declare module 'seyfert' {
    interface Logger {
        success(...args: unknown[]): void;
        cmd(...args: unknown[]): void;
    }
}

Now you can use them throughout your bot:

import { createEvent } from 'seyfert';

export default createEvent({
    data: { name: 'botReady', once: true },
    run(user, client) {
        client.logger.success(`${user.username} is online!`);
    },
});

Webhook Error Reporting

A common pattern is to report errors to a Discord webhook for monitoring:

import { Embed, type Client } from 'seyfert';

const WEBHOOK_ID = 'your-webhook-id';
const WEBHOOK_TOKEN = 'your-webhook-token';

async function reportError(client: Client, error: Error, context?: string) {
    const embed = new Embed()
        .setTitle('Error Report')
        .setDescription(`\`\`\`\n${error.stack ?? error.message}\n\`\`\``)
        .setColor(0xFF0000)
        .setTimestamp();

    if (context) {
        embed.addFields({ name: 'Context', value: context });
    }

    await client.webhooks.writeMessage(WEBHOOK_ID, WEBHOOK_TOKEN, {
        body: { embeds: [embed] },
    });
}

Use it in your error handlers:


export default class MyCommand extends Command {
    async onRunError(ctx: CommandContext, error: unknown) {
        await ctx.editOrReply({ content: 'Something went wrong!' });

        if (error instanceof Error) {
            await reportError(ctx.client, error, `Command: /${ctx.fullCommandName}`);
        }
    }
}