Using arguments in commands

Sometimes when using commands, you may want to get data from the user and change the response accordingly. In this section, you'll create a command that pulls a string from the message and says it back to the user!

String arguments

A string argument is simply the text after the command name and prefix. For example: ?say Hi there! would cause the argument to be Hi there!. It's quite simple to create one.

First, go into your first folder and make a new file called say.js. Once you have it, set up your command class and everything just like the one in the meow command.

const { Command } = require('discord.js-commando');

module.exports = class SayCommand extends Command {
	constructor(client) {
		super(client, {
			name: 'say',
			aliases: ['parrot', 'copy'],
			group: 'first',
			memberName: 'say',
			description: 'Replies with the text you provide.',
		});
	}

	run(message) {
		// ...
	}
};

The args field is simply an array of objects, each containing data for that argument.

module.exports = class SayCommand extends Command {
	constructor(client) {
		super(client, {
			// ...
			args: [
				{
					key: 'text',
					prompt: 'What text would you like the bot to say?',
					type: 'string',
				},
			],
		});
	}
};

See? Simple.

• key is the name of the argument. When you define it in your run method, this is what you'll be using.
• prompt is the text that displays if the user doesn't provide arguments. If someone uses ?say by itself, that prompt will ask for the text.
• type is the type of the argument. It can be many things, including string, integer, user, member, etc.

Adding more args is as simple as adding another object to the array, like so:

module.exports = class SayCommand extends Command {
	constructor(client) {
		super(client, {
			// ...
			args: [
				{
					key: 'text',
					prompt: 'What text would you like the bot to say?',
					type: 'string',
				},
				{
					key: 'otherThing',
					prompt: 'What is this other useless thing?',
					type: 'string',
				},
			],
		});
	}
};

You can also set arguments to default to a specific value:

module.exports = class SayCommand extends Command {
	constructor(client) {
		super(client, {
			// ...
			args: [
				// ...
				{
					key: 'otherThing',
					prompt: 'What is this other useless thing?',
					type: 'string',
					'default': 'dog',
				},
			],
		});
	}
};

As you can see, they're very powerful things.

Head on over to your run method and set the text arg to a variable and return the text to the user.

module.exports = class SayCommand extends Command {
	constructor(client) {
		// ...
	}

	run(message, { text }) {
		return message.reply(text);
	}
};

And there you have it, a say command using args!

Resulting code

If you want to compare your code to the code we've constructed so far, you can review it over on the GitHub repository here (opens new window).