feat: Switch to NodeJS's EventEmitter as parent class (#55)

Rapsssito · web-flow · commit d21bb0b8d0ce · 2020-06-16T02:20:13.000+02:00
Switch to NodeJS's EventEmitter as parent class as part of the migration to a NodeJS out-of-the-box approach (#41). BREAKING CHANGE: Sockets will no longer return RemovableListeners when calling their addListener() method. Now they inherit all the event methods from Node's EventEmitter class.
diff --git a/.eslintrc.json b/.eslintrc.json
@@ -1,4 +1,5 @@
 {
+    "parser": "babel-eslint",
     "plugins": ["prettier", "jest", "jsdoc"],
     "env": {
         "es6": true,
diff --git a/.gitignore b/.gitignore
@@ -50,4 +50,3 @@ buck-out/
 
 # Tests
 coverage
-!coverage/coverage-final.json
diff --git a/coverage/coverage-final.json b/coverage/coverage-final.json
diff --git a/package.json b/package.json
@@ -59,8 +59,9 @@
     "@semantic-release/npm": "^7.0.0",
     "@types/jest": "^25.1.3",
     "@types/react-native": "^0.61.17",
+    "babel-eslint": "^10.1.0",
     "babel-jest": "^24.9.0",
-    "eslint": "^6.6.0",
+    "eslint": "^6.8.0",
     "eslint-config-prettier": "^6.5.0",
     "eslint-plugin-jest": "^23.6.0",
     "eslint-plugin-jsdoc": "^21.0.0",
@@ -74,6 +75,7 @@
     "typescript": "^3.8.2"
   },
   "dependencies": {
-    "buffer": "^5.4.3"
+    "buffer": "^5.4.3",
+    "events": "^3.1.0"
   }
 }
diff --git a/src/TcpServer.js b/src/TcpServer.js
@@ -18,56 +18,59 @@ export default class TcpServer extends TcpSocket {
         this._eventEmitter = eventEmitter;
     }
 
-    close() {
-        this.destroy();
-        this._connections.forEach((clientSocket) => clientSocket.destroy());
+    /**
+     * @override
+     */
+    _registerEvents() {
+        super._registerEvents();
+        this._connectionsListener = this._eventEmitter.addListener('connection', (evt) => {
+            if (evt.id !== this._id) return;
+            this._onConnection(evt.info);
+            this.emit('connection', evt.info);
+        });
     }
 
     /**
-     * @param {(arg0: number) => void} callback
+     * @override
      */
-    getConnections(callback) {
-        callback(this._connections.length);
+    _unregisterEvents() {
+        super._unregisterEvents();
+        this._connectionsListener?.remove();
     }
 
     /**
-     * @param {{ port: number; host: any; }} options
-     * @param {(arg0: any) => void} callback
+     * @param {{ port: number; host: string; reuseAddress?: boolean}} options
+     * @param {(arg0: any) => void} [callback]
      * @returns {TcpServer}
      */
     listen(options, callback) {
-        let gotOptions = {};
-        // Normalize args
-        if (typeof arguments[0] === 'number') {
-            // Deprecated old version: listen(port[, host][, callback])
-            console.warn(
-                'TcpServer.listen(port[, host][, callback]) is deprecated and has been moved to TcpServer.listen(options[, callback]). It will be removed in react-native-tcp-socket@4.0.0'
-            );
-            gotOptions.port = arguments[0];
-            /** @type {string} */
-            gotOptions.host = arguments[1];
-            callback = arguments[2];
-        } else {
-            gotOptions = options;
-        }
+        const gotOptions = { ...options };
         gotOptions.host = gotOptions.host || '0.0.0.0';
-        const connectListener = this.on('connect', (ev) => {
-            connectListener.remove();
+        this.once('connect', (ev) => {
             if (callback) callback(ev.address);
         });
-        this._registerEvents();
-        this.on('connection', (ev) => this._onConnection(ev.info));
         Sockets.listen(this._id, gotOptions);
         return this;
     }
 
+    /**
+     * @param {(arg0: number) => void} callback
+     */
+    getConnections(callback) {
+        callback(this._connections.length);
+    }
+
+    close() {
+        this.destroy();
+        this._connections.forEach((clientSocket) => clientSocket.destroy());
+    }
+
     /**
      * @private
      * @param {{ id: number; address: string; }} info
      */
     _onConnection(info) {
-        const socket = new TcpSocket(info.id, this._eventEmitter);
-        socket.setAsAlreadyConnected(info.address);
+        const socket = new TcpSocket(info.id, this._eventEmitter, info.address);
         this._connections.push(socket);
         this.connectionCallback(socket);
     }
diff --git a/src/TcpSocket.js b/src/TcpSocket.js
@@ -1,6 +1,7 @@
 'use strict';
 
 import { NativeModules, Image } from 'react-native';
+import { EventEmitter } from 'events';
 const Buffer = (global.Buffer = global.Buffer || require('buffer').Buffer);
 const Sockets = NativeModules.TcpSockets;
 
@@ -10,27 +11,6 @@ const STATE = {
     CONNECTED: 2,
 };
 
-class RemovableListener {
-    /**
-     * @param {import("react-native").EmitterSubscription} listener
-     * @param {import("react-native").NativeEventEmitter} eventEmitter
-     */
-    constructor(listener, eventEmitter) {
-        this._listener = listener;
-        this._eventEmitter = eventEmitter;
-        this._removed = false;
-    }
-
-    isRemoved() {
-        return this._removed;
-    }
-
-    remove() {
-        this._eventEmitter.removeSubscription(this._listener);
-        this._removed = true;
-    }
-}
-
 /**
  * @typedef {{
  * port: number;
@@ -45,99 +25,71 @@ class RemovableListener {
  * tlsCert?: any,
  * }} ConnectionOptions
  */
-export default class TcpSocket {
+export default class TcpSocket extends EventEmitter {
     /**
      * Initialices a TcpSocket.
      *
      * @param {number} id
      * @param {import('react-native').NativeEventEmitter} eventEmitter
+     * @param {string} [address]
      */
-    constructor(id, eventEmitter) {
+    constructor(id, eventEmitter, address) {
+        super();
         this._id = id;
         this._eventEmitter = eventEmitter;
         /** @type {number} */
         this._state = STATE.DISCONNECTED;
-        /** @type {RemovableListener[]} */
-        this._listeners = [];
-    }
-
-    /**
-     * Adds a listener to be invoked when events of the specified type are emitted by the `TcpSocket`.
-     * An optional calling `context` may be provided.
-     * The data arguments emitted will be passed to the listener callback.
-     *
-     * @param {string} event  Name of the event to listen to
-     * @param {(arg0: any) => void} callback Function to invoke when the specified event is emitted
-     * @param {any} [context] Optional context object to use when invoking the listener
-     * @returns {RemovableListener}
-     */
-    on(event, callback, context) {
-        const newListener = this._selectListener(event, callback, context);
-        const removableListener = new RemovableListener(newListener, this._eventEmitter);
-        this._listeners.push(removableListener);
-        return removableListener;
+        this._registerEvents();
+        if (address != undefined) this._setConnected(address);
     }
 
     /**
-     * @private
-     * @param {string} event
-     * @param {function(any):void} callback
-     * @param {any} [context]
+     * @protected
      */
-    _selectListener(event, callback, context) {
-        switch (event) {
-            case 'data':
-                return this._eventEmitter.addListener(
-                    'data',
-                    (evt) => {
-                        if (evt.id !== this._id) return;
-                        const bufferTest = Buffer.from(evt.data, 'base64');
-                        callback(bufferTest);
-                    },
-                    context
-                );
-            case 'error':
-                return this._eventEmitter.addListener(
-                    'error',
-                    (evt) => {
-                        if (evt.id !== this._id) return;
-                        callback(evt.error);
-                    },
-                    context
-                );
-            default:
-                return this._eventEmitter.addListener(
-                    event,
-                    (evt) => {
-                        if (evt.id !== this._id) return;
-                        callback(evt);
-                    },
-                    context
-                );
-        }
+    _registerEvents() {
+        this._unregisterEvents();
+        this._dataListener = this._eventEmitter.addListener('data', (evt) => {
+            if (evt.id !== this._id) return;
+            const bufferTest = Buffer.from(evt.data, 'base64');
+            this.emit('data', bufferTest);
+        });
+        this._errorListener = this._eventEmitter.addListener('error', (evt) => {
+            if (evt.id !== this._id) return;
+            this._onError();
+            this.emit('error', evt.error);
+        });
+        this._closeListener = this._eventEmitter.addListener('close', (evt) => {
+            if (evt.id !== this._id) return;
+            this._onClose();
+            this.emit('close', evt.error);
+        });
+        this._connectListener = this._eventEmitter.addListener('connect', (evt) => {
+            if (evt.id !== this._id) return;
+            this._onConnect(evt.address);
+            this.emit('connect', evt.address);
+        });
     }
 
     /**
-     * @deprecated
+     * @protected
      */
-    off() {
-        console.warn(
-            'TCPSocket.off() is deprecated and produces no effect, please use the listener remove() method instead.'
-        );
+    _unregisterEvents() {
+        this._dataListener?.remove();
+        this._errorListener?.remove();
+        this._closeListener?.remove();
+        this._connectListener?.remove();
     }
 
     /**
      * @param {ConnectionOptions} options
      * @param {(address: string) => void} [callback]
      */
     connect(options, callback) {
-        this._registerEvents();
         const customOptions = { ...options };
         // Normalize args
         customOptions.host = customOptions.host || 'localhost';
         customOptions.port = Number(customOptions.port) || 0;
-        const connectListener = this.on('connect', (ev) => {
-            connectListener.remove();
+        this.once('connect', (ev) => {
             if (callback) callback(ev.address);
         });
         // Timeout
@@ -246,36 +198,19 @@ export default class TcpSocket {
         }
     }
 
-    /**
-     * @protected
-     */
-    _registerEvents() {
-        this.on('connect', (ev) => this._onConnect(ev.address));
-        this.on('close', () => this._onClose());
-        this.on('error', () => this._onError());
-    }
-
-    /**
-     * @private
-     */
-    _unregisterEvents() {
-        this._listeners.forEach((listener) => (listener.isRemoved() ? listener.remove() : null));
-        this._listeners = [];
-    }
-
     /**
      * @private
      * @param {string} address
      */
     _onConnect(address) {
-        this.setConnected(address);
+        this._setConnected(address);
     }
 
     /**
      * @private
      */
     _onClose() {
-        this.setDisconnected();
+        this._setDisconnected();
     }
 
     /**
@@ -316,14 +251,6 @@ export default class TcpSocket {
         );
     }
 
-    /**
-     * @param {string} address
-     */
-    setAsAlreadyConnected(address) {
-        this._registerEvents();
-        this.setConnected(address);
-    }
-
     /**
      * @private
      * @param {string | Buffer | Uint8Array} buffer
@@ -347,15 +274,15 @@ export default class TcpSocket {
      * @private
      * @param {string} address
      */
-    setConnected(address) {
+    _setConnected(address) {
         this._state = STATE.CONNECTED;
         this._address = address;
     }
 
     /**
      * @private
      */
-    setDisconnected() {
+    _setDisconnected() {
         if (this._state === STATE.DISCONNECTED) return;
         this._unregisterEvents();
         this._state = STATE.DISCONNECTED;
diff --git a/yarn.lock b/yarn.lock

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,5 @@`
`1`	`1`	`{`
	`2`	`+ "parser": "babel-eslint",`
`2`	`3`	`"plugins": ["prettier", "jest", "jsdoc"],`
`3`	`4`	`"env": {`
`4`	`5`	`"es6": true,`
Original file line number	Diff line number	Diff line change
`@@ -50,4 +50,3 @@ buck-out/`
`50`	`50`
`51`	`51`	`# Tests`
`52`	`52`	`coverage`
`53`		`-!coverage/coverage-final.json`