implement EventEmitter compatible with browsers

packages/web3-core/src/web3_event_emitter.ts

@@ -15,7 +15,7 @@ You should have received a copy of the GNU Lesser General Public License
 along with web3.js.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-import { EventEmitter } from 'events';
+import { EventEmitter } from 'web3-utils';
 
 export type Web3EventMap = Record<string, unknown>;
 export type Web3EventKey<T extends Web3EventMap> = string & keyof T;

packages/web3-eth-accounts/src/common/common.ts

@@ -15,9 +15,8 @@ You should have received a copy of the GNU Lesser General Public License
 along with web3.js.  If not, see <http://www.gnu.org/licenses/>.
 */
 import pkg from 'crc-32';
-import { EventEmitter } from 'events';
+import { EventEmitter, bytesToHex, hexToBytes, uint8ArrayConcat } from 'web3-utils';
 import type { Numbers } from 'web3-types';
-import { bytesToHex, hexToBytes, uint8ArrayConcat } from 'web3-utils';
 import { TypeOutput } from './types.js';
 import { intToUint8Array, toType, parseGethGenesis } from './utils.js';
 import goerli from './chains/goerli.js';

packages/web3-providers-ws/test/unit/__mocks__/isomorphic-ws.ts

@@ -15,7 +15,7 @@ You should have received a copy of the GNU Lesser General Public License
 along with web3.js.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-import { EventEmitter } from 'events';
+import { EventEmitter } from 'web3-utils';
 
 export default class WebSocket extends EventEmitter {
 	public readyState: number;

packages/web3-utils/src/event_emitter.ts

@@ -0,0 +1,104 @@
+/*
+This file is part of web3.js.
+
+web3.js is free software: you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+web3.js is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with web3.js.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+import { EventEmitter as NodeEventEmitter } from 'events';
+
+type Callback = (params: any) => void | Promise<void>;
+
+export class InBrowserEventEmitter extends EventTarget {
+	private _listeners: Record<string, Callback[]> = {};
+	private maxListeners = Number.MAX_SAFE_INTEGER;
+
+	public on(eventName: string, fn: Callback) {
+		super.addEventListener(eventName, fn as EventListener);
+		this._addToListeners(eventName, fn);
+		return this;
+	}
+
+	public once(eventName: string, fn: Callback) {
+		const onceCallback = async (params: unknown) => {
+			await fn(params);
+			this.off(eventName, onceCallback);
+		};
+		return this.on(eventName, onceCallback);
+	}
+
+	public off(eventName: string, fn: Callback) {
+		super.removeEventListener(eventName, fn as EventListener);
+		this._removeFromListeners(eventName, fn);
+		return this;
+	}
+
+	public emit(eventName: string, params: unknown) {
+		const event = new CustomEvent(eventName, { detail: params });
+		return super.dispatchEvent(event);
+	}
+
+	public listenerCount(eventName: string): number {
+		const eventListeners = this._listeners[eventName];
+		return eventListeners ? eventListeners.length : 0;
+	}
+
+	public listeners(eventName: string): Callback[] {
+		return this._listeners[eventName] || [];
+	}
+
+	public eventNames(): string[] {
+		return Object.keys(this._listeners);
+	}
+
+	public removeAllListeners() {
+		this._listeners = {};
+		return this;
+	}
+
+	public setMaxListeners(maxListeners: number) {
+		this.maxListeners = maxListeners;
+		return this;
+	}
+
+	public getMaxListeners(): number {
+		return this.maxListeners;
+	}
+
+	private _addToListeners(eventName: string, fn: Callback) {
+		if (!this._listeners[eventName]) {
+			this._listeners[eventName] = [];
+		}
+		this._listeners[eventName].push(fn);
+	}
+
+	private _removeFromListeners(eventName: string, fn: Callback) {
+		const eventListeners = this._listeners[eventName];
+		if (eventListeners) {
+			const index = eventListeners.indexOf(fn);
+			if (index !== -1) {
+				eventListeners.splice(index, 1);
+			}
+		}
+	}
+}
+
+// eslint-disable-next-line import/no-mutable-exports
+export let EventEmitter: typeof NodeEventEmitter;
+// Check if the code is running in a Node.js environment
+if (typeof window === 'undefined') {
+	EventEmitter = NodeEventEmitter;
+} else {
+	// Fallback for the browser environment
+	EventEmitter = InBrowserEventEmitter as unknown as typeof NodeEventEmitter;
+}

packages/web3-utils/src/index.ts

@@ -16,6 +16,7 @@ along with web3.js.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 export * from './converters.js';
+export * from './event_emitter.js';
 export * from './validation.js';
 export * from './formatter.js';
 export * from './hash.js';

packages/web3-utils/test/unit/socket_provider.test.ts

@@ -15,8 +15,8 @@ You should have received a copy of the GNU Lesser General Public License
 along with web3.js.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-import { EventEmitter } from 'stream';
 import { Web3APIPayload, EthExecutionAPI, JsonRpcResponse, Web3ProviderStatus } from 'web3-types';
+import { EventEmitter } from '../../src/event_emitter';
 // eslint-disable-next-line import/no-relative-packages
 import { sleep } from '../../../../fixtures/utils';
 import { SocketProvider } from '../../src/socket_provider';