feat(command parser): add regexPrefix client option

src/events/command-handler/CoreMessageParser.ts

@@ -19,13 +19,16 @@ export class CoreEvent extends Event<Events.Message> {
 
 		let prefix = null;
 		const mentionPrefix = this.getMentionPrefix(message.content);
+		const { regexPrefix } = this.context.client.options;
 		if (mentionPrefix) {
 			if (message.content.length === mentionPrefix.length) {
 				message.client.emit(Events.MentionPrefixOnly, message);
 				return;
 			}
 
 			prefix = mentionPrefix;
+		} else if (regexPrefix) {
+			prefix = regexPrefix;
 		} else {
 			const prefixes = await message.client.fetchPrefix(message);
 			const parsed = this.getPrefix(message.content, prefixes);

src/events/command-handler/CorePrefixedMessage.ts

@@ -8,9 +8,10 @@ export class CoreEvent extends Event<Events.PrefixedMessage> {
 		super(context, { event: Events.PrefixedMessage });
 	}
 
-	public run(message: Message, prefix: string) {
+	public run(message: Message, prefix: string | RegExp) {
 		// Retrieve the command name and validate:
-		const prefixLess = message.content.slice(prefix.length).trim();
+		const trimLength = prefix instanceof RegExp ? prefix.exec(message.content)?.[0].length ?? 0 : prefix.length;
+		const prefixLess = message.content.slice(trimLength).trim();
 		const spaceIndex = prefixLess.indexOf(' ');
 		const name = spaceIndex === -1 ? prefixLess : prefixLess.slice(0, spaceIndex);
 		if (!name) {

src/lib/SapphireClient.ts

@@ -48,6 +48,25 @@ export interface SapphireClientOptions {
 	 */
 	defaultPrefix?: SapphirePrefix;
 
+	/**
+	 * The regex prefix, an alternative to a mention or regular prefix to allow creating natural language command messages
+	 * @since 1.0.0
+	 * @default undefined
+	 * @example
+	 * ```ts
+	 * /^(hey +)?(?:bot)[,! ]/i
+	 * /**
+	 * Matches:
+	 * - hey bot,
+	 * - hey bot!
+	 * - hey bot
+	 * - bot,
+	 * - bot!
+	 * - bot
+	 * ```
+	 */
+	regexPrefix?: RegExp;
+
 	/**
 	 * The prefix hook, by default it is a callback function that returns [[SapphireClientOptions.defaultPrefix]].
 	 * @since 1.0.0

src/lib/structures/Command.ts

@@ -138,9 +138,11 @@ export interface CommandOptions extends AliasPieceOptions {
 
 export interface CommandContext extends Record<PropertyKey, unknown> {
 	/**
-	 * The prefix used to run this command
+	 * The prefix used to run this command.
+	 *
+	 * This is a string for the mention and default prefix, and a RegExp for the `regexPrefix`.
 	 */
-	prefix: string;
+	prefix: string | RegExp;
 	/**
 	 * The alias used to run this command
 	 */

src/lib/types/Events.ts

@@ -120,9 +120,9 @@ declare module 'discord.js' {
 		[Events.PiecePostLoad]: [Store<Piece>, Piece];
 		[Events.MentionPrefixOnly]: [Message];
 		[Events.EventError]: [Error, EventErrorPayload];
-		[Events.PrefixedMessage]: [Message, string];
-		[Events.UnknownCommandName]: [Message, string];
-		[Events.UnknownCommand]: [Message, string, string];
+		[Events.PrefixedMessage]: [Message, string | RegExp];
+		[Events.UnknownCommandName]: [Message, string | RegExp];
+		[Events.UnknownCommand]: [Message, string, string | RegExp];
 		[Events.PreCommandRun]: [PreCommandRunPayload];
 		[Events.CommandDenied]: [UserError, CommandDeniedPayload];
 		[Events.CommandAccepted]: [CommandAcceptedPayload];