Options

Options are declared by name, and their values arrive typed. There is no getString("name"): the name you wrote is the property you read.

options: {
	user: option.user({ required: true }),
	reason: option.string({ maxLength: 512 }),
	days: option.integer({
		choices: [
			{ name: "One day", value: 1 },
			{ name: "A week", value: 7 },
		],
	}),
},
run: ({ options }) => {
	options.user;   // APIUser
	options.reason; // string | undefined
	options.days;   // 1 | 7 | undefined
},

Kinds

Required and optional

required: true makes the value its type; otherwise it can be undefined. Nubis orders required options before optional ones when it registers the command, as Discord requires, so you can declare them in whatever order reads best.

Settings

Every kind takes description (defaults to the option's name) and required. Then:

Choices become types

A choice list narrows the value to exactly its values, so a switch over them is checked by TypeScript:

options: {
	size: option.string({
		required: true,
		choices: [
			{ name: "Small", value: "s" },
			{ name: "Large", value: "l" },
		],
	}),
},
run: ({ options, reply }) => {
	// options.size: "s" | "l"
	switch (options.size) {
		case "s":
			return reply("Small it is.");
		case "l":
			return reply("Large it is.");
	}
},

Autocomplete

autocomplete returns suggestions for what the user has typed so far; Nubis sends Discord the first 25. Unlike choices, the user can still send something that wasn't suggested, so the value's type stays string (or number).

const FRUIT = ["apple", "apricot", "banana", "blueberry", "cherry"];

options: {
	fruit: option.string({
		required: true,
		autocomplete: ({ value }) =>
			FRUIT.filter((name) => name.startsWith(value.toLowerCase()))
				.slice(0, 25)
				.map((name) => ({ name, value: name })),
	}),
},

The handler gets value (always a string while typing), the other options as typed so far, interaction and api. An option can have choices or autocomplete, not both.

Checked when you define them

Nubis applies Discord's rules when the command is loaded, with the command and option named in the error:

NubisError: /mod ban option "days": integer choices must be whole numbers.

It checks names, description lengths, at most 25 options and 25 choices, choice name and value lengths, minLength against maxLength and minValue against maxValue.