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Recipes

Yuna Parser

Yuna is an advanced parser for prefix/text commands in Seyfert. It provides custom syntax for named options, dynamic prefixes, and watchers.

Installing...
pnpm add yunaforseyfert

Setup

Override the default command handling with Yuna's parser and resolver:

import { Client, type ParseClient } from 'seyfert';
import { HandleCommand } from 'seyfert/lib/commands/handle';
import { Yuna } from 'yunaforseyfert';

const client = new Client({
    commands: {
        prefix: () => ['!', '?'],
        reply: () => true,
    },
});

client.setServices({
    handleCommand: class extends HandleCommand {
        argsParser = Yuna.parser({
            syntax: { namedOptions: ['-', '--'] },
        });

        resolveCommandFromContent = Yuna.resolver({
            client: this.client,
            afterPrepare: (metadata) => {
                this.client.logger.info(`Loaded ${metadata.commands.length} commands`);
            },
        });
    },
});

await client.start();

declare module 'seyfert' {
    interface UsingClient extends ParseClient<Client<true>> {}

    interface InternalOptions {
        withPrefix: true;
    }
}

Remember to enable prefix support via InternalOptions module augmentation as shown above.

Dynamic Prefix Per Guild

Use an async prefix function to return different prefixes per guild:

import { Client } from 'seyfert';

const client = new Client({
    commands: {
        prefix: async (message) => {
            const config = await db.getGuildConfig(message.guildId);
            return config?.prefixes ?? ['!'];
        },
        reply: () => true,
    },
});

Watchers

Watchers let you monitor text command interactions over time — useful for commands that need follow-up input:

import { Command, Declare, type CommandContext } from 'seyfert';
import { Watch, Yuna } from 'yunaforseyfert';

@Declare({
    name: 'help',
    description: 'Interactive help',
})
@Watch({
    idle: 60_000,
    beforeCreate(ctx) {
        // Cancel any existing watcher for this user + command
        const existing = Yuna.watchers.find(ctx.client, {
            userId: ctx.author.id,
            command: this,
        });
        if (existing) existing.stop('replaced');
    },
})
export default class HelpCommand extends Command {
    async run(ctx: CommandContext) {
        await ctx.write({ content: 'What do you need help with? Reply with a topic.' });
    }
}

On this page

Setup
Dynamic Prefix Per Guild
Watchers