choice argument type

types/choice.js

@@ -0,0 +1,19 @@
+const { ArgumentType } = require('discord.js-commando');
+const { list } = require('../util/Util');
+
+class ChoiceArgumentType extends ArgumentType {
+	constructor(client) {
+		super(client, 'choice');
+	}
+
+	validate(value, msg, arg) {
+		if (arg.choices.includes(value.toLowerCase())) return true;
+		return `Invalid ${arg.label}, please enter either ${list(arg.choices, 'or')}.`;
+	}
+
+	parse(value) {
+		return value.toLowerCase();
+	}
+}
+
+module.exports = ChoiceArgumentType;