feat: should be able to register other nodejs event emitters

src/handler/sern.ts

@@ -1,4 +1,4 @@
-import type { DiscordEvent } from '../types/handler';
+import type { DiscordEvent, EventEmitterRegister } from '../types/handler';
 
 import { ApplicationCommandType, Client } from 'discord.js';
 
@@ -11,20 +11,25 @@ import { onInteractionCreate } from './events/interactionCreate';
 import { match, P } from 'ts-pattern';
 import { Err, Ok } from 'ts-results';
 import { CommandType } from './structures/enums';
+import { isDiscordEvent } from './utilities/predicates';
 
 export function init(wrapper: Wrapper) {
     const { events, client } = wrapper;
-    if (events !== undefined) eventObserver(client, events);
+    if (events !== undefined)  {
+      eventObserver(client, events);
+    }  
     onReady(wrapper);
     onMessageCreate(wrapper);
     onInteractionCreate(wrapper);
 }
 
-//TODO : Add event listener for any other generic node js event emitter
-function eventObserver(client: Client, events: DiscordEvent[]) {
-    events.forEach(([event, cb]) => {
-        if (event === 'ready') throw Error(SernError.ReservedEvent);
-        fromEvent(client, event, cb).subscribe();
+function eventObserver(client: Client, events: (DiscordEvent | EventEmitterRegister)[]) {
+    events.forEach((event) => {
+        if(isDiscordEvent(event)) {
+          fromEvent(client, event[0], event[1]).subscribe();
+        } else {
+          fromEvent(event[0], event[1], event[2]).subscribe();
+        }
     });
 }
 

src/handler/structures/wrapper.ts

@@ -1,5 +1,5 @@
 import type { Client } from 'discord.js';
-import type { DiscordEvent } from '../../types/handler';
+import type { DiscordEvent, EventEmitterRegister } from '../../types/handler';
 
 /**
  * An object to be passed into Sern.Handler constructor.
@@ -14,7 +14,7 @@ interface Wrapper {
     readonly client: Client;
     readonly defaultPrefix?: string;
     readonly commands: string;
-    readonly events?: DiscordEvent[];
+    readonly events?: (DiscordEvent | EventEmitterRegister)[];
 }
 
 export default Wrapper;

src/handler/utilities/predicates.ts

@@ -9,6 +9,7 @@ import type {
     SelectMenuInteraction,
     UserContextMenuCommandInteraction,
 } from 'discord.js';
+import type { DiscordEvent, EventEmitterRegister } from '../..';
 
 
 
@@ -40,4 +41,9 @@ export function isUserContextMenuCmd(i : CommandInteraction) : i is UserContextM
 export function isPromise<T>(promiseLike : Awaitable<T>) : promiseLike is Promise<T> {
     const keys = new Set(Object.keys(promiseLike));
     return keys.has('then') && keys.has('catch');
-}
+}
+
+export function isDiscordEvent(el : DiscordEvent | EventEmitterRegister) : el is DiscordEvent {
+    return el.length === 2;
+}
+

src/types/handler.ts

@@ -5,7 +5,7 @@ import type {
     MessageOptions,
     MessagePayload,
 } from 'discord.js';
-
+import type { EventEmitter } from 'events';
 // Anything that can be sent in a `<TextChannel>#send` or `<CommandInteraction>#reply`
 export type possibleOutput<T = string> = T | (MessagePayload & MessageOptions);
 export type Nullish<T> = T | undefined | null;
@@ -17,6 +17,9 @@ export type ParseType<T> = {
 export type Args = ParseType<{ text: string[]; slash: SlashOptions }>;
 
 export type DiscordEvent = ParseType<{ [K in keyof ClientEvents]: (...args: ClientEvents[K]) => Awaitable<void> }>;
+export type EventEmitterRegister = [ emitter: EventEmitter, k : string, cb : (...args: unknown[]) => Awaitable<void>];
+
+
 
 export type SlashOptions = Omit<CommandInteractionOptionResolver, 'getMessage' | 'getFocused'>;