Revert "events: allow monitoring error events"

This reverts commit 5cb0de9.

Author: MylesBorins

doc/api/events.md

@@ -155,18 +155,6 @@ myEmitter.emit('error', new Error('whoops!'));
 // Prints: whoops! there was an error
 ```
 
-It is possible to monitor `'error'` events without consuming the emitted error
-by installing a listener using the symbol `errorMonitor`.
-
-```js
-constmyEmitter=newMyEmitter();
-myEmitter.on(EventEmitter.errorMonitor, (err) => {
-MyMonitoringTool.log(err);
-});
-myEmitter.emit('error', newError('whoops!'));
-// Still throws and crashes Node.js
-```
-
 ## Capture Rejections of Promises
 
 > Stability: 1 - captureRejections is experimental.
@@ -360,19 +348,6 @@ the event emitter instance, the event’s name and the number of attached
 listeners, respectively.
 Its `name` property is set to `'MaxListenersExceededWarning'`.
 
-### `EventEmitter.errorMonitor`
-<!-- YAML
-added: v12.16.0
--->
-
-This symbol shall be used to install a listener for only monitoring `'error'`
-events. Listeners installed using this symbol are called before the regular
-`'error'` listeners are called.
-
-Installing a listener using this symbol does not change the behavior once an
-`'error'` event is emitted, therefore the process will still crash if no
-regular `'error'` listener is installed.
-
 ### `emitter.addListener(eventName, listener)`
 <!-- YAML
 added: v0.1.26

lib/events.js

@@ -60,7 +60,6 @@ const {
 }=require('internal/util/inspect');
 
 constkCapture=Symbol('kCapture');
-constkErrorMonitor=Symbol('events.errorMonitor');
 
 functionEventEmitter(opts){
 EventEmitter.init.call(this,opts);
@@ -90,13 +89,6 @@ ObjectDefineProperty(EventEmitter, 'captureRejections', {
 enumerable: true
 });
 
-ObjectDefineProperty(EventEmitter,'errorMonitor',{
-value: kErrorMonitor,
-writable: false,
-configurable: true,
-enumerable: true
-});
-
 // The default for captureRejections is false
 ObjectDefineProperty(EventEmitter.prototype,kCapture,{
 value: false,
@@ -270,11 +262,9 @@ EventEmitter.prototype.emit = function emit(type, ...args) {
 letdoError=(type==='error');
 
 constevents=this._events;
-if(events!==undefined){
-if(doError&&events[kErrorMonitor]!==undefined)
-this.emit(kErrorMonitor, ...args);
+if(events!==undefined)
 doError=(doError&&events.error===undefined);
-}elseif(!doError)
+elseif(!doError)
 returnfalse;
 
 // If there is no 'error' event listener then throw.