feat(SlashCommandBuilder): create setDefaultPermission function (#19)

Co-authored-by: Vlad Frangu <kingdgrizzle@gmail.com>

src/interactions/slashCommands/Assertions.ts

@@ -38,6 +38,12 @@ export function validateDescription(description: unknown): asserts description i
 	ow(description, 'description', descriptionPredicate);
 }
 
+const defaultPermissionPredicate = ow.boolean;
+
+export function validateDefaultPermission(value: unknown): asserts value is boolean {
+	ow(value, 'default_permission', defaultPermissionPredicate);
+}
+
 const maxArrayLengthPredicate = ow.array.maxLength(25);
 
 export function validateMaxOptionsLength(options: unknown): asserts options is ToAPIApplicationCommandOptions[] {

src/interactions/slashCommands/SlashCommandBuilder.ts

@@ -1,8 +1,13 @@
 import type { APIApplicationCommandOption } from 'discord-api-types/v9';
 import { mix } from 'ts-mixer';
-import { assertReturnOfBuilder, validateMaxOptionsLength, validateRequiredParameters } from './Assertions';
-import { SharedNameAndDescription } from './mixins/NameAndDescription';
+import {
+	assertReturnOfBuilder,
+	validateDefaultPermission,
+	validateMaxOptionsLength,
+	validateRequiredParameters,
+} from './Assertions';
 import { SharedSlashCommandOptions } from './mixins/CommandOptions';
+import { SharedNameAndDescription } from './mixins/NameAndDescription';
 import { SlashCommandSubcommandBuilder, SlashCommandSubcommandGroupBuilder } from './SlashCommandSubcommands';
 
 @mix(SharedSlashCommandOptions, SharedNameAndDescription)
@@ -22,6 +27,12 @@ export class SlashCommandBuilder {
 	 */
 	public readonly options: ToAPIApplicationCommandOptions[] = [];
 
+	/**
+	 * Whether the command is enabled by default when the app is added to a guild
+	 * @default true
+	 */
+	public readonly defaultPermission: boolean | undefined = undefined;
+
 	/**
 	 * Returns the final data that should be sent to Discord.
 	 *
@@ -33,9 +44,27 @@ export class SlashCommandBuilder {
 			name: this.name,
 			description: this.description,
 			options: this.options.map((option) => option.toJSON()),
+			default_permission: this.defaultPermission,
 		};
 	}
 
+	/**
+	 * Sets whether the command is enabled by default when the application is added to a guild.
+	 *
+	 * **Note**: If set to `false`, you will have to later have to `PUT` the permissions for this command.
+	 * @param value Whether or not to enable this command by default
+	 *
+	 * @see https://discord.com/developers/docs/interactions/slash-commands#permissions
+	 */
+	public setDefaultPermission(value: boolean) {
+		// Assert the value matches the conditions
+		validateDefaultPermission(value);
+
+		Reflect.set(this, 'defaultPermission', value);
+
+		return this;
+	}
+
 	/**
 	 * Adds a new subcommand group to this command
 	 * @param input A function that returns a subcommand group builder, or an already built builder

tests/SlashCommands.test.ts

@@ -73,6 +73,14 @@ describe('Slash Commands', () => {
 			).toThrowError();
 		});
 
+		test('GIVEN valid default_permission THEN does not throw error', () => {
+			expect(() => SlashCommandAssertions.validateDefaultPermission(true)).not.toThrowError();
+		});
+
+		test('GIVEN invalid default_permission THEN throw error', () => {
+			expect(() => SlashCommandAssertions.validateDefaultPermission(null)).toThrowError();
+		});
+
 		test('GIVEN valid array of options or choices THEN does not throw error', () => {
 			expect(() => SlashCommandAssertions.validateMaxOptionsLength([])).not.toThrowError();
 
@@ -206,6 +214,10 @@ describe('Slash Commands', () => {
 				// @ts-expect-error Checking if not providing anything, or an invalid return type causes an error
 				expect(() => getBuilder().addBooleanOption(() => new Collection())).toThrowError();
 			});
+
+			test('GIVEN valid builder with defaultPermission false THEN does not throw error', () => {
+				expect(() => getBuilder().setName('foo').setDescription('foo').setDefaultPermission(false)).not.toThrowError();
+			});
 		});
 
 		describe('Builder with subcommand (group) options', () => {