FAQ

Short answers to what people ask first, about runtimes, JavaScript, discord.js, state, databases and tests.

Short answers, each with the chapter that explains it.

Does MeoCord run on Bun, or only Node.js?

Both. The bot runs on Node.js 22.13 or later, or on Bun, and meocord start runs it on the runtime that started the CLI: bun run start:prod under Bun, npm run start:prod under Node. See Which runtime the bot runs on.

Can I write a bot in plain JavaScript?

No. Controllers, commands and guards are declared with TypeScript's decorators, and injection reads the constructor types TypeScript emits for them. A new project is set up for TypeScript, and meocord build compiles it.

Can I use discord.js directly?

Yes. Handlers receive discord.js's own interactions, messages and reactions, and a service can inject the Client. MeoCord makes the client from @MeoCord({ clientOptions }), and anything discord.js can do is still there. See Where discord.js begins.

Where does state live?

In services. A controller or service is made once and shared by every call, so a Map on a service holds across calls, and so do interceptors, exception filters, pipes and observers. A guard is made for each call and keeps nothing between them, unless it's bound: supplied by a provider, listed in services or injected by another class, in which case every call shares one instance. State that must survive a restart, or be shared between shard processes, belongs in a database that a service wraps. See What lives how long.

Does MeoCord include a database?

No. Use any client library. Provide the connection from an async factory in @MeoCord({ providers }): MeoCord awaits it before the bot logs in, and injects it into the classes that ask for it. Close it in its onShutdown. The database recipe shows it with PostgreSQL. A native driver works with self-contained builds, which pack it into dist.

Does the bot reload while I edit it?

Yes. meocord start --dev rebuilds on every change and restarts the bot, one bot at a time. It watches meocord.config.ts and tsconfig.json too, and a change to a development .env file restarts the bot without a rebuild. Commands go to commands.developmentGuild, if set, where they update at once, and they're registered only when they changed. See Development and production.

When do I need sharding?

When Discord asks for it: past about 2,500 servers, a bot that doesn't shard can't log in. Before that, one connection is simpler. sharding: { shards: 'auto' } runs every shard in one process, and mode: 'process' gives each shard a process of its own, spreading the work over CPU cores. See Sharding.

How do I test a handler without Discord?

Build a testing module with the controller, and run the handler with invoke, through the same guards, cooldowns and filters the bot uses, with mocks in place of discord.js's objects. See Testing.

Why decorators?

A handler's routing, guards, cooldowns and validation are declared where the handler is, and MeoCord reads them at startup: nothing is wired to discord.js by hand, and a test can inspect what a handler is set up with. It's the model NestJS uses on the server, applied to a bot.

Where do I report a bug or ask a question?

In the issue tracker. The contributing guide covers working on MeoCord itself.