Add global middleware

Functions the same as command middleware except it applies to ALL commands including base commands, and will be run before any command-specific middleware is run.

src/lib/bot/Bot.ts

@@ -8,6 +8,7 @@ import { Command } from '../command/Command';
 import { CommandLoader } from '../command/CommandLoader';
 import { CommandRegistry } from '../command/CommandRegistry';
 import { CommandDispatcher } from '../command/CommandDispatcher';
+import { MiddlewareFunction } from '../types/MiddlewareFunction';
 
 /**
  * The Discord.js Client instance. Contains bot-specific [storage]{@link Bot#storage},
@@ -30,6 +31,7 @@ export class Bot extends Client
 	public version: string;
 	public disableBase: string[];
 	public config: any;
+	public _middleware: MiddlewareFunction[];
 
 	public storage: LocalStorage;
 	public guildStorages: GuildStorageRegistry<string, GuildStorage>;
@@ -148,6 +150,9 @@ export class Bot extends Client
 		 */
 		this.disableBase = botOptions.disableBase || [];
 
+		// Middleware function storage for the bot instance
+		this._middleware = [];
+
 		this._guildDataStorage = new LocalStorage('storage/guild-storage');
 		this._guildSettingStorage = new LocalStorage('storage/guild-settings');
 		this._guildStorageLoader = new GuildStorageLoader(this);
@@ -328,6 +333,43 @@ export class Bot extends Client
 		this._guildStorageLoader.cleanGuilds(this._guildDataStorage, this._guildSettingStorage);
 	}
 
+	/**
+	 * Adds a middleware function to be used when any command is run
+	 * to make modifications to args or determine if the command can
+	 * be run. Takes a function that will receive the message object
+	 * and the array of args.
+	 *
+	 * A middleware function must return an array where the first item
+	 * is the message object and the second item is the args array.
+	 * If a middleware function returns a string, or throws a string/error,
+	 * it will be sent to the calling channel as a message and the command
+	 * execution will be aborted. If a middleware function does not return
+	 * anything or returns something other than an array or string, it will
+	 * fail silently.
+	 *
+	 * Example:
+	 * ```js
+	 * this.use((message, args) => [message, args.map(a => a.toUpperCase())]);
+	 * ```
+	 * This will add a middleware function to all commands that will attempt
+	 * to transform all args to uppercase. This will of course fail if any
+	 * of the args are not a string.
+	 *
+	 * Note: Middleware functions should only be added to the bot one time each,
+	 * and thus should not be added within any sort of event or loop.
+	 * Multiple middleware functions can be added to the via multiple calls
+	 * to this method
+	 * @memberof Bot
+	 * @instance
+	 * @param {MiddlewareFunction} fn Middleware function. `(message, args) => [message, args]`
+	 * @returns {Bot} This Bot instance
+	 */
+	public use(fn: MiddlewareFunction): this
+	{
+		this._middleware.push(fn);
+		return this;
+	}
+
 //#region Discord.js events
 
 	public on(event: 'channelCreate', listener: (channel: Channel) => void): this;

src/lib/command/Command.ts

@@ -1,6 +1,6 @@
-import { Bot } from '../bot/Bot';
 import { PermissionResolvable, Message } from 'discord.js';
-
+import { Bot } from '../bot/Bot';
+import { MiddlewareFunction } from '../types/MiddlewareFunction';
 import { CommandInfo } from '../types/CommandInfo';
 import { ArgOpts } from '../types/ArgOpts';
 
@@ -28,7 +28,7 @@ export class Command<T extends Bot>
 	public overloads: string;
 
 	public _classloc: string;
-	public _middleware: Array<(message: Message, args: string[]) => Promise<[Message, any[]]> | [Message, any[]]>;
+	public _middleware: MiddlewareFunction[];
 
 	public constructor(bot: T, info: CommandInfo = null)
 	{
@@ -253,19 +253,17 @@ export class Command<T extends Bot>
 	 * ```
 	 * This will add a middleware function to the command that will attempt
 	 * to transform all args to uppercase. This will of course fail if any
-	 * of the args are not a string. This could be ensured with the `stringArgs`
-	 * `argOpts` flag, or via another middleware function added before this one
-	 * that converts all args to strings.
+	 * of the args are not a string.
 	 *
 	 * Note: Middleware functions should only be added to a command one time each,
 	 * and thus should be added in the Command's constructor. Multiple middleware
 	 * functions can be added to a command via multiple calls to this method
 	 * @memberof Command
 	 * @instance
-	 * @param {Function} fn Middleware function. `(message, args) => [message, args]`
+	 * @param {MiddlewareFunction} fn Middleware function. `(message, args) => [message, args]`
 	 * @returns {Command} This command instance
 	 */
-	public use(fn: (message: Message, args: any[]) => Promise<[Message, any[]]> | [Message, any[]]): this
+	public use(fn: MiddlewareFunction): this
 	{
 		this._middleware.push(fn);
 		return this;

src/lib/command/CommandDispatcher.ts

@@ -1,4 +1,5 @@
 import { PermissionResolvable, TextChannel, User } from 'discord.js';
+import { MiddlewareFunction } from '../types/MiddlewareFunction';
 import { Message } from '../types/Message';
 import { GuildStorage } from '../storage/GuildStorage';
 import { Command } from '../command/Command';
@@ -54,11 +55,12 @@ export class CommandDispatcher<T extends Bot>
 			.filter(a => a !== '');
 
 		let middlewarePassed: boolean = true;
-		for (let middleware of command._middleware)
+		let middleware: MiddlewareFunction[] = this._bot._middleware.concat(command._middleware);
+		for (let func of middleware)
 			try
 			{
 				let result: Promise<[Message, any[]]> | [Message, any[]] =
-					middleware.call(command, message, args);
+					func.call(command, message, args);
 				if (result instanceof Promise) result = await result;
 				if (!(result instanceof Array))
 				{

src/lib/command/middleware/Expect.ts

@@ -1,10 +1,11 @@
 import { Bot } from '../../bot/Bot';
+import { MiddlewareFunction } from '../../types/MiddlewareFunction';
 import { ExpectArgType } from '../../types/ExpectArgType';
 import { Message } from '../../types/Message';
 import { Command } from '../Command';
 import { GuildMember, Role, TextChannel, User } from 'discord.js';
 
-export function expect<T extends Bot, U extends Command<T>>(argTypes: { [name: string]: ExpectArgType }): (message: Message, args: any[]) => [Message, any[]]
+export function expect<T extends Bot, U extends Command<T>>(argTypes: { [name: string]: ExpectArgType }): MiddlewareFunction
 {
 	return function(message, args): [Message, any[]]
 	{

src/lib/command/middleware/Middleware.ts

@@ -1,8 +1,8 @@
-import { Message } from '../../types/Message';
-import { resolveArgs } from './ResolveArgs';
-import { expect } from './Expect';
 import { Bot } from '../../bot/Bot';
 import { Command } from '../Command';
+import { expect } from './Expect';
+import { resolveArgs } from './ResolveArgs';
+import { MiddlewareFunction } from '../../types/MiddlewareFunction';
 import { ResolveArgType } from '../../types/ResolveArgType';
 import { ExpectArgType } from '../../types/ExpectArgType';
 
@@ -34,8 +34,7 @@ export class Middleware
 	 * @returns {Function} <pre class="prettyprint"><code>(message: Message, args: any[]) => [Message, any[]]</code></pre>
 	 */
 	public static resolveArgs: <T extends Bot, U extends Command<T>>(argTypes: { [name: string]: ResolveArgType }) =>
-		(message: Message, args: any[]) =>
-			Promise<[Message, any[]]> = resolveArgs;
+		MiddlewareFunction = resolveArgs;
 
 	/**
 	 * Takes an object mapping argument names to argument types that
@@ -63,6 +62,5 @@ export class Middleware
 	 * @returns {Function} <pre class="prettyprint"><code>(message: Message, args: any[]) => [Message, any[]]</code></pre>
 	 */
 	public static expect: <T extends Bot, U extends Command<T>>(argTypes: { [name: string]: ExpectArgType }) =>
-		(message: Message, args: any[]) =>
-			[Message, any[]] = expect;
+		MiddlewareFunction = expect;
 }

src/lib/command/middleware/ResolveArgs.ts

@@ -1,11 +1,12 @@
 import { Bot } from '../../bot/Bot';
 import { Message } from '../../types/Message';
+import { MiddlewareFunction } from '../../types/MiddlewareFunction';
 import { ResolveArgType } from '../../types/ResolveArgType';
 import { Util } from '../../Util';
 import { Command } from '../Command';
 import { Collection, GuildMember, Role, TextChannel, User } from 'discord.js';
 
-export function resolveArgs<T extends Bot, U extends Command<T>>(argTypes: { [name: string]: ResolveArgType }): (message: Message, args: any[]) => Promise<[Message, any[]]>
+export function resolveArgs<T extends Bot, U extends Command<T>>(argTypes: { [name: string]: ResolveArgType }): MiddlewareFunction
 {
 	return async function(message, args): Promise<[Message, any[]]>
 	{

src/lib/types/MiddlewareFunction.ts

@@ -0,0 +1,11 @@
+import { Message } from './Message';
+
+export type MiddlewareFunction = (message: Message, args: any[]) => Promise<[Message, any[]]> | [Message, any[]];
+
+/**
+ * @typedef {Function} MiddlewareFunction A function that takes a Message object and an array of args,
+ * does anything with them, and returns an array where the first item is the Message object and the
+ * second item is the array of args.<br><br>It should be noted that the command dispatcher will attempt
+ * to bind the called Command instance to the middleware function, so if it is not an arrow function
+ * `this` within a middleware function will be the Command instance at runtime
+ */