Merge pull request #330 from Web3Auth/feat/replace-eventemitter

Replace event emitter with typed emitter

package.json

@@ -91,6 +91,7 @@
     "tsconfig-paths-webpack-plugin": "^4.1.0",
     "tslib": "^2.6.3",
     "tsx": "^4.16.3",
+    "typed-emitter": "^2.1.0",
     "typescript": "^5.5.4"
   },
   "peerDependencies": {
@@ -133,7 +134,7 @@
     "elliptic": "^6.5.6",
     "enc-utils": "^3.0.0",
     "end-of-stream": "^1.4.4",
-    "eventemitter3": "^5.0.1",
+    "events": "^3.3.0",
     "fast-safe-stringify": "^2.1.1",
     "json-stable-stringify": "^1.1.1",
     "loglevel": "^1.9.1",

src/core/PopupHandler.ts

@@ -1,5 +1,6 @@
 import { SecurePubSub } from "@toruslabs/secure-pub-sub";
-import { EventEmitter } from "eventemitter3";
+import { EventEmitter } from "events";
+import type { default as TypedEmitter } from "typed-emitter";
 
 import { LoginError } from "./errors";
 import { getPopupFeatures } from "./utils";
@@ -11,11 +12,11 @@ export interface PopupResponse {
   error?: string;
 }
 
-export interface PopupHandlerEvents {
-  close: [];
-}
+export type PopupHandlerEvents = {
+  close: () => void;
+};
 
-class PopupHandler extends EventEmitter<PopupHandlerEvents> {
+class PopupHandler extends (EventEmitter as new () => TypedEmitter<PopupHandlerEvents>) {
   url: string;
 
   target: string;
@@ -31,6 +32,8 @@ class PopupHandler extends EventEmitter<PopupHandlerEvents> {
   timeout: number;
 
   constructor({ url, target, features, timeout = 30000 }: { url: string; target?: string; features?: string; timeout?: number }) {
+    // Disabling the rule here, as it is a false positive.
+    // eslint-disable-next-line constructor-super
     super();
     this.url = url;
     this.target = target || "_blank";

src/jrpc/jrpc.ts

@@ -41,9 +41,9 @@ export function createErrorMiddleware(log: ConsoleLike): JRPCMiddleware<unknown,
   };
 }
 
-export interface StreamEvents {
+export type StreamEvents = {
   notification: (arg1: JRPCRequest<unknown>) => boolean;
-}
+};
 
 export function createStreamMiddleware(): { events: SafeEventEmitter<StreamEvents>; middleware: JRPCMiddleware<unknown, unknown>; stream: Duplex } {
   const idMap: IdMap = {};

src/jrpc/jrpcEngine.ts

@@ -17,9 +17,9 @@ import {
 import { SafeEventEmitter } from "./safeEventEmitter";
 import { SerializableError } from "./serializableError";
 
-export interface JrpcEngineEvents {
-  notification: (arg1: string) => void;
-}
+export type JrpcEngineEvents = {
+  notification: (...args: unknown[]) => void;
+};
 
 /**
  * A JSON-RPC request and response processor.
@@ -411,9 +411,9 @@ export function createEngineStream(opts: EngineStreamOptions): Duplex {
   return stream;
 }
 
-export interface ProviderEvents {
-  data: (error: unknown, message: string) => void;
-}
+export type ProviderEvents = {
+  data: (error: unknown, message: unknown) => void;
+};
 
 export interface SafeEventEmitterProvider extends SafeEventEmitter<ProviderEvents> {
   sendAsync: <T, U>(req: JRPCRequest<T>) => Promise<U>;
@@ -452,7 +452,7 @@ export function providerFromEngine(engine: JRPCEngine): SafeEventEmitterProvider
   };
   // forward notifications
   if (engine.on) {
-    engine.on("notification", (message: string) => {
+    engine.on("notification", (message) => {
       provider.emit("data", null, message);
     });
   }

src/jrpc/safeEventEmitter.ts

@@ -1,10 +1,6 @@
 /* eslint-disable @typescript-eslint/no-explicit-any */
-import { EventEmitter } from "eventemitter3";
-
-type Handler = (...args: any[]) => void;
-interface EventMap {
-  [k: string]: Handler | Handler[] | undefined;
-}
+import { EventEmitter } from "events";
+import type { default as TypedEmitter, EventMap } from "typed-emitter";
 
 function safeApply<T, A extends any[]>(handler: (this: T, ...handlerArgs: A) => void, context: T, args: A): void {
   try {
@@ -26,8 +22,8 @@ function arrayClone<T>(arr: T[]): T[] {
   return copy;
 }
 
-export class SafeEventEmitter<T extends EventEmitter.ValidEventTypes> extends EventEmitter<T> {
-  emit(type: EventEmitter.EventNames<T>, ...args: any[]): boolean {
+export class SafeEventEmitter<T extends EventMap = EventMap> extends (EventEmitter as { new <E extends EventMap>(): TypedEmitter<E> })<T> {
+  emit<E extends keyof T>(type: E, ...args: Parameters<T[E]>): boolean {
     let doError = type === "error";
 
     const events: EventMap = (this as any)._events;
@@ -63,8 +59,8 @@ export class SafeEventEmitter<T extends EventEmitter.ValidEventTypes> extends Ev
     if (typeof handler === "function") {
       safeApply(handler, this, args);
     } else {
-      const len = handler.length;
-      const listeners = arrayClone(handler);
+      const len = (handler as any[]).length;
+      const listeners = arrayClone(handler as any[]);
       for (let i = 0; i < len; i += 1) {
         safeApply(listeners[i], this, args);
       }