Knub

Knub is a JavaScript/TypeScript framework for creating Discord bots.

High-level overview

A bot built on Knub consists of one or more plugins. For each plugin context (e.g. a Discord server ("guild")), Knub will create a new instance of each plugin that should be loaded for the context. A plugin context is usually just one server, but in the future it can also be a group of servers.

A plugin is simply a plain object that conforms to the PluginBlueprint interface.

Each plugin has access to a set of utility modules for setting up commands, event listeners, user configuration, etc. Plugins are also able to specify public interfaces that other plugins can use for interoperability, as well as plugin dependencies.

The primary goals for Knub are:

Safety first — Knub aims to make it easy to write safe code by default
Predictability — any "magic" within Knub should be easy to reason about, and ideally the magic is left out in the first place
Automatic context-awareness — guild plugins only have access to the context of the guild (server) they're loaded in by default
Extensive built-in functionality — for common bot requirements

Documentation

The documentation for Knub is currently a work in progress. For now, see the examples below and browse projects built on Knub, such as Zeppelin.

Examples

For simplicity, the examples below only showcase a very limited subset of Knub's features. Full examples for loading per-context configuration, advanced commands, event handling, global plugins, etc. is coming in the near future.

TypeScript example

import Eris from "eris";
import { Knub, typedGuildPlugin, typedGuildCommand, BasePluginType } from "knub";

interface CustomPluginType extends BasePluginType {
  state: {
    counter: number;
  };
}

// We use a type helper, typedGuildCommand(), here to allow TypeScript to infer argument types and other types within the command object ("blueprint")
// See the JavaScript example further below for an example that uses plain objects instead!
const CounterCommand = typedGuildCommand<CustomPluginType>()({
  trigger: "counter",
  // Permission requirement must always be specified,
  // even if explicitly to mark the command public as done here
  permission: null,
  run({ message, pluginData }) {
    // Type of `pluginData.state.counter` is `number`
    message.channel.createMessage(`Counter value: ${++pluginData.state.counter}`);
  },
});

// Another type helper here: typedGuildPlugin()
const CounterPlugin = typedGuildPlugin<CustomPluginType>()({
  name: "counter-plugin",

  commands: [
    CounterCommand,
  ],

  onLoad({ state }) {
    // Initialize counter for CounterCommand
    state.counter = 0;
  },
});

const client = new Eris("my-bot-token");
const knub = new Knub(client, {
  guildPlugins: [
    CounterPlugin,
  ]
});

knub.run();

JavaScript example

This example doesn't use the type helpers used in the TypeScript example above, and instead uses plain objects wherever possible.

const Eris = require("eris");
const { Knub, baseCommandParameterTypeHelpers } = require("knub");

const t = baseCommandParameterTypeHelpers;

const MyCommand = {
  trigger: "echo",
  signature: {
    text: t.string(),
  },
  permission: null,
  run({ args, message }) {
    message.channel.createMessage(args.text);
  },
};

const OtherCommand = {
  trigger: "ping",
  permission: null,
  run({ message }) {
    message.channel.createMessage("Pong!");
  },
};

const MyPlugin = {
  name: "my-plugin",
  commands: [
    MyCommand,
    OtherCommand,
  ],
};

const client = new Eris("my-bot-token");
const knub = new Knub(client, {
  guildPlugins: [
    MyPlugin,
  ]
});

knub.run();

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