Using template types in declarations

[bitomic]

Most of the provided classes have a member to access to the AkairoClient, which commonly is a class that inherits from it. However, when using TypeScript, it complains if you try to access to your custom client's members because the client of, let's say, Command class is of type AkairoClient.

// client.ts
export default class CustomClient extends AkairoClient {
	private version: string
	constructor() {
		super({
			// akairo options
		}, {
			// discord.js options
		})
		this.version = '1.0.0'
	}
}

If I want to write a command like:

import { Command } from 'discord-akairo'
import { Message } from 'discord'
class VersionCommand extends Command {
	constructor() {
		super('version', {
			aliases: [ 'v' ]
		})
	}
	exec(message: Message) {
		return message.channel.send(`I am currently running on version ${this.client.version}`)
	}
}

You will receive the following warning:

Property 'version' does not exist on type 'AkairoClient'.ts(2339)

However, if you ignore it and run the bot, it will reply with the version properly. The problem is in the types definition.

A suggestion is to add template types to these classes, so you could:

import { Command } from 'discord-akairo'
import { Message } from 'discord'
import CustomClient from './client'
class VersionCommand extends Command<CustomClient> {
	constructor() {
		super('version', {
			aliases: [ 'v' ]
		})
	}
	exec(message: Message) {
		return message.channel.send(`I am currently running on version ${this.client.version}`)
	}
}

Where Command.client would not be of type AkairoClient but <Client extends AkairoClient>. Now I could access to my custom properties properly, without having to use // @ts-ignore.

Hopefully the point is clear enough!

[TymanWasTaken]

My solution to this was to just make a custom command class (extending Command) and override the client property of it to the correct type

[bitomic]

They are pretty much equivalent, but I consider using a template type is a more elegant solution. But I never thought on that way, my current method was // @ts-ignore so I may use yours if they don't implement this/until they do.