mrmBot-Matrix/docs/custom-commands.md

Custom Commands

esmBot has a flexible command handler, allowing you to create new commands and categories simply by creating new files. This page will provide a reference for creating new commands.

Directory Structure

The bot loads commands from subdirectories inside of the commands directory, which looks something like this by default:

commands
  - fun
    > cat.js
    > ...
  - general
    > help.js
    > ping.js
    > ...
  - image-editing
    > caption.js
    > speed.js
    > ...

As you can see, each command is grouped into categories, which are represented by subdirectories. To create a new category, you can simply create a new directory inside of the commands directory, and to create a new command, you can create a new JS file under one of those subdirectories.

Commnand Structure

It's recommended to use the Command class located in classes/command.js to create a new command in most cases. This class provides various parameters and fields that will likely be useful when creating a command. Here is a simple example of a working command file:

import Command from "../../classes/command.js";

class HelloCommand extends Command {
  async run() {
    return "Hello world!";
  }

  static description = "A simple command example";
  static aliases = ["helloworld"];
}

export default HelloCommand;

As you can see, the first thing we do is import the Command class. We then create a new class for the command that extends that class to provide the needed parameters. We then define the command function, which is named run. Some static parameters, including the command description and an alias for the command, helloworld, are also defined. Finally, once everything in the command class is defined, we export the new class to be loaded as a module by the command handler.

The default command name is the same as the filename that you save it as, excluding the .js file extension. If you ever want to change the name of the command, just rename the file.

The parameters available to your command consist of the following:

• this.client: An instance of an Eris Client, useful for getting info or performing lower-level communication with the Discord API.
• this.cluster: The ID of the eris-fleet cluster that the command is being run from. This should be a number greater than or equal to 0.
• this.worker: The ID of the current eris-fleet worker. This should be a number greater than or equal to 0.
• this.ipc: An eris-fleet IPC instance, useful for communication between worker processes.
• this.origOptions: The raw options object provided to the command by the command handler.
• this.type: The type of message that activated the command. Can be "classic" (a regular message) or "application" (slash commands).
• this.channel: An Eris TextChannel object of the channel that the command was run in, useful for getting info about a server and how to respond to a message.
• this.author: An Eris User object of the user who ran the command, or a Member object identical to this.member if run in a server as a slash command.
• this.member: An Eris Member object of the server member who ran the command. When running the command outside of a server, this parameter is undefined when run as a "classic" command or a User object identical to this.author when run as a slash command.
• this.options: When run as a "classic" command, this is an object of special arguments (e.g. --argument=true) passed to the command. These arguments are stored in a key/value format, so following the previous example, this.options.argument would return true. When run as a slash command, this is an object of every argument passed to the command.

Some options are only available depending on the context/original message type, which can be checked with this.type. The options only available with "classic" messages are listed below:

• this.message: An Eris Message object of the message that the command was run from, useful for interaction.
• this.args: An array of text arguments passed to the command.
• this.content: A string of the raw content of the command message, excluding the prefix and command name.
• this.reference: An object that's useful if you ever decide to reply to a user inside the command. You can use Object.assign to combine your message content with this parameter.

The options only available with "application"/slash commands are listed below:

• this.interaction: An Eris CommandInteraction object of the incoming slash command data.
• this.optionsArray: A raw array of command options. Should rarely be used.

Some static fields are also available and can be set depending on your command. These fields are listed below:

• description: Your command's description, which is shown in the help command.
• aliases: An array of command aliases. People will be able to run the command using these as well as the normal command name.
• arguments: An array of command argument types, which are shown in the help command.
• flags: An array of objects specifying command flags, or special arguments, that will be shown when running help <command> or a slash command. Example:

static flags = [{
  name: "argument",
  type: Constants.ApplicationCommandOptionTypes.STRING, // translates to 3, see https://discord.com/developers/docs/interactions/application-commands#application-command-object-application-command-option-type
  description: "Does a thing",
  ...
}];

• slashAllowed: Specifies whether or not the command is available via slash commands.
• directAllowed: Specifies whether or not a command is available in direct messages.

The run Function

The main JS code of your command is specified in the run function. This function should return a Promise of your command output, which is why the run function is an async function by default. The return value inside the Promise should be either a string or an object; you should return a string whenever you intend to reply with plain text, or an object if you intend to reply with something else, such as an embed or attachment.