feat(Plugins)!: improve event system (#32)

Author: execaman

src/Main/Player.ts

@@ -5,25 +5,31 @@ import { isString } from "../Functions";
 import { NodeManager } from "../Node";
 import { VoiceManager } from "../Voice";
 import { Playlist, Queue, QueueManager, Track } from "../Queue";
+import { PlayerPlugin } from "./index";
 import type {
   CreateQueueOptions,
   PlayerEventMap,
   PlayerOptions,
   PlayOptions,
-  PlayerPlugin,
   PluginRecord,
   RepeatMode,
   SearchOptions,
   SearchResult,
   CreateNodeOptions,
   PlayerInstanceOptions,
   QueueContext,
+  PluginEventMap,
+  MergeUnionType,
 } from "../Typings";
 
+type ConstrainEventMap<T> = {
+  [K in keyof T]: T[K] extends any[] ? T[K] : never;
+};
+
 export class Player<
   Context extends Record<string, unknown> = QueueContext,
-  Plugins extends PlayerPlugin[] = PlayerPlugin[],
-> extends EventEmitter<Plugins[number]["eventMap"] & PlayerEventMap> {
+  Plugins extends PlayerPlugin[] = [],
+> extends EventEmitter<ConstrainEventMap<PlayerEventMap & MergeUnionType<PluginEventMap<Plugins[number]>>>> {
   #initialized = false;
   #initPromise: Promise<void> | null = null;
 
@@ -52,7 +58,10 @@ export class Player<
     this.plugins = {} as PluginRecord<Plugins>;
 
     if (_options.plugins !== undefined) {
-      for (const plugin of _options.plugins) (this.plugins as { [x: string]: PlayerPlugin })[plugin.name] = plugin;
+      for (const plugin of _options.plugins) {
+        if (!(plugin instanceof PlayerPlugin)) throw new Error("Invalid plugin(s)");
+        (this.plugins as { [x: string]: PlayerPlugin })[plugin.name] = plugin;
+      }
       delete _options.plugins;
     }
 

src/Main/Plugin.ts

@@ -0,0 +1,7 @@
+import type { Player } from "./index";
+
+export abstract class PlayerPlugin<EventMap extends Record<string, unknown[]> = {}> {
+  declare protected _: EventMap;
+  abstract readonly name: string;
+  abstract init(player: Player): void;
+}

src/Main/index.ts

@@ -1 +1,2 @@
+export * from "./Plugin";
 export * from "./Player";

src/Plugins/LavaLyrics.ts

@@ -2,7 +2,8 @@ import { HttpStatusCode } from "axios";
 import { OPType } from "../Typings";
 import { Routes } from "../Constants";
 import { isString } from "../Functions";
-import type { BaseEventPayload, CommonPluginInfo, JsonObject, PlayerPlugin } from "../Typings";
+import { PlayerPlugin } from "../Main";
+import type { BaseEventPayload, CommonPluginInfo, JsonObject } from "../Typings";
 import type { Node } from "../Node";
 import type { Queue } from "../Queue";
 import type { Player } from "../Main";
@@ -47,24 +48,22 @@ export namespace LavaLyrics {
 
   export type Event = LyricsFoundEvent | LyricsNotFoundEvent | LyricsLineEvent;
 
-  export type EventMap = {
-    lyricsFound: [queue: Queue, lyrics: Lyrics];
-    lyricsNotFound: [queue: Queue];
-    lyricsLine: [queue: Queue, line: LyricsLine, index: number, skipped: boolean];
-  };
-
   export interface PluginOptions {
     skipTrackSource?: boolean;
   }
 
-  export class Plugin implements PlayerPlugin {
-    name = "lavalyrics" as const;
-    eventMap!: EventMap;
+  export class Plugin extends PlayerPlugin<{
+    lyricsFound: [queue: Queue, lyrics: Lyrics];
+    lyricsNotFound: [queue: Queue];
+    lyricsLine: [queue: Queue, line: LyricsLine, index: number, skipped: boolean];
+  }> {
+    name = "lavalyrics";
 
     #player!: Player;
     skipTrackSource: boolean;
 
     constructor(options?: PluginOptions) {
+      super();
       this.skipTrackSource = options?.skipTrackSource === true;
     }
 

src/Typings/Main/Player.ts

@@ -6,11 +6,11 @@ import type { DefaultPlayerOptions } from "../../Constants";
 import type { Node } from "../../Node";
 import type { VoiceState } from "../../Voice";
 import type { Playlist, Queue, Track } from "../../Queue";
-import type { Player } from "../../Main";
+import type { PlayerPlugin } from "../../Main";
 
 type ExcludeLast<T extends any[]> = T extends [...infer Items, any] ? Items : never;
 
-export interface PlayerEventMap extends Record<string & {}, any> {
+export interface PlayerEventMap {
   init: [];
 
   nodeConnect: [node: Node, ...ExcludeLast<NodeEventMap["connect"]>];
@@ -36,15 +36,6 @@ export interface PlayerEventMap extends Record<string & {}, any> {
   trackFinish: [queue: Queue, track: Track, reason: TrackEndReason];
 }
 
-/**
- * Represents the structure of a plugin
- */
-export interface PlayerPlugin {
-  readonly name: string;
-  eventMap: Record<string & {}, any[]>;
-  init(player: Player): void;
-}
-
 /**
  * Constructs a record type mapping plugins by their names
  */

src/Typings/Utility.ts

@@ -1,3 +1,5 @@
+import type { PlayerPlugin } from "../Main";
+
 /**
  * Represents an empty object
  */
@@ -30,6 +32,16 @@ export type NonNullableProp<T, P extends keyof T> = {
   [K in keyof T]: K extends P ? NonNullable<T[K]> : T[K];
 };
 
+/**
+ * Merges a union type into one
+ */
+export type MergeUnionType<U> = (U extends any ? (i: U) => void : never) extends (i: infer I) => void ? I : never;
+
+/**
+ * Extracts the event map of a plugin
+ */
+export type PluginEventMap<Plugin> = Plugin extends PlayerPlugin<infer EventMap> ? EventMap : {};
+
 /**
  * Queue context, extend via module declaration
  */