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    0.4.8 • Public • Published

    JADL Command Handler

    This new version of the command handler is WIP and not stable, use with caution.


    If you're going to use the decorators built into the command handler, make sure to set "experimentalDecorators": true in your tsconfig.json

    Creating a Command Handler

    Create a command handler with the CommandHandler class

    import { CommandHandler } from '@jadl/cmd'
    import { WaveCommand } from './commands/WaveCommand' // example command
    const commands = new CommandHandler(worker, [
      // your command classes

    Creating a command

    Commands are classes that will be filled with decorator to dictate their functionality

    Our main decorator for a command is @Command(name: string, description: string)

    Once you've declared your class, you create a method to run the command through, and mark it with a @Run() decorator

    You can return a traditional MessageTypes and it will respond to the command with that. Here's an example;

    import { Command } from '@jadl/cmd'
    @Command('wave', 'Wave at someone!') // sets the command name to /wave
    export class WaveCommand {
      @Run() // marks this method as the main running command
      wave () {
        return 'Hello!'

    Simplest command in the book. Lets get a bit more advanced.

    Accessing data with parameter decorators

    Using parameter decorators is how we access all of our important data, to make your command a real command

    Many of them exist and allow for adding and using interaction options, or just accessing your normal data objects

    e.g let's add a user via the Options.User decorator. This will create a Discord interaction user option

    import { Command, Run, Worker, Author } from '@jadl/cmd'
    import { Embed } from '@jadl/embed' // optional, but used for embeds!
    @Command('hello', 'Say hello!')
    export class HelloCommand {
      hello (
        @Worker() worker: Bot, // creates a paramater that is your worker
        @Author() author: APIUser // gets the user who sent the command
      ) {
        // you can now use this parameter as it's actual value! making it super easy to do what you need to do
        return new Embed()
          .description(`Hey <@${author.id}>! Thanks for saying hi! My name is ${worker.user.username}!`)
    // note, discord-api-types is EXTREMELY useful and will let you add types for all of these

    Some helpful decorators:

    • @Worker, gets the main worker
    • @Interaction gets the interaction object
    • @Guild gets the guild
    • @Author gets the running user
    • @Member gets the running member
    • @Me gets the worker's member in this guild

    (many more to come) // WIP

    Creating options

    The @Options.[] decorator is used to apply options to a command. For example @Options.String('name', 'description', { options })

    e.g let's add a user via the Options.User decorator. This will create a Discord interaction user option

    import { Command, Run, Options } from '@jadl/cmd'
    import { Embed } from '@jadl/embed'
    @Command('wave', 'Wave at someone!')
    export class WaveCommand {
      wave (
        @Options.User('user', 'User to wave at', {
          required: true
        }) user: APIUser // creates an option accepting type user
      ) {
        // you can now use this parameter as it's actual value! making it super easy to do what you need to do
        return new Embed()
          .description(`Hey <@${user.id}>! Someone waved at you`)

    Extra command decorators


    For permissions v2 there is a Permissions(permission) decorator

    import { Command, Permissions, Run } from '@jadl/cmd'
    @Command('admin', 'Only users with Manager Server can run this command')
    @Permissions('manageServer') // only Manage Server permissions (overrideable by permissions v2)
    export class AdminCommand {
      run () {
        superSecretThing() // only people who are allowed to run the command in the server can do it

    Targets & message/user commands

    You can create a user or message command by passing the type of command you'd like to the @Command() 3rd parameter

    And then you can use the @Targets decorator as a value for those targets. Be careful to make sure to use the correct target for your command

    e.g lets make our wave command a user command!

    import { Command, Run, Targets, Author } from '@jadl/cmd'
    import { Embed } from '@jadl/embed'
    import { ApplicationCommandType } from 'discord-api-types/v9'
    @Command('Wave at user', undefined, ApplicationCommandType.User)
    export class WaveCommand {
      wave (
        @Targets.User() user: APIUser, // gets the user who the command was ran ON
        @Author() author: APIUser // gets the user who the command was ran FROM
      ) {
        return new Embed()
          .description(`Hey <@${user.id}>! <@${author.id}> waved at you!`)

    Middleware / interceptor decorators

    With decorators it's super easy to create and use decorator for specific commands. There's a few built in. For example @UserPerms()

    @Command('ban', 'Ban a user')
    class BanCommand {
      @UserPerms('administrator') // this will require the user has the administrator permission
      run () {
        // run ban

    Creating your own

    You can also make your own decorators with the Decorators object

    There are 3 types of decorators

    Base Decorators

    Base decorators go above the command class similar to the @Command() decorator. These are mostly used for internal things, but it's available

    You can create this with the Decorators.createBaseDecorator() method

    Command Decorators

    Command decorators are the decorators that go over the method being ran, and are generally used as middleware / interceptors, or just defining extra metadata about the command

    You can create these with the Decorators.createCommandDecorator() method

    e.g let's create a specific user only decorator


    import { Decorators } from '@jadl/cmd' // global utility for everything decorators
    export const UserLocked = Decorators.createCommandDecorator<[
      // options
      userId: string
    ]>(([userId], cmd) => {
      // Use the canRun array of functions
      cmd.canRun.push((interaction, handler) => { // interaction being the raw object
        // return a boolean of whether or not the author is the user locked
        return interaction.user.id === userId
      // you can also use the onRun array of functions to disregard returning and errors

    You can now use this in your command like so

    import { UserLocked } from '../decorators/UserLocked'
    @Command('wave', 'Wave at someone!')
    export class WaveCommand {
      @UserLocked('277183033344524288') // this will now apply the above canRun method
      run () {
        return 'Wave!' // only ran if the user matches the user locked to this command

    Parameter decorators

    Parameter decorators are used to pass data to the running method when a command has been ran

    The essential way this works is that you're giving the command handler a function that will be ran and positioned to your method based on the parameter

    You can create these with the Decorators.createParameterDecorator() method

    e.g let's make a database decorator


    import { Decorators } from '@jadl/cmd'
    // you can add options the same was as was done above, however we don't need that here
    export const Db = Decorators.createParameterDecorator((options) => {
      return async (interaction, { worker }) => { // this method is ran EVERYTIME a command is ran, and it's return value is what shows up on the parameter for your method
        return await worker.db.guildSettings.get(interaction.guild_id) // returns the guild's database

    Now we can use the @Db() decorator shorthand in our method

    import { Db } from '../decorators/Db'
    @Command('wave', 'Wave at someone!')
    export class WaveCommand {
      wave (
        @Db() db: GuildSettings, // makes our db parameter
        @Author() author: APIUser // and you can add as many of these params as you'd like!
      ) {
        // and now db will be whatever was returned in the Db decorator!
        if (!db.users.includes(author.id)) return "You can't do that!"
        return 'Wave!'


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