Listen to All Emitted Events in Node.js

Question

In Node.js is there any way to listen to all events emitted by an EventEmitter object?

e.g., can you do something like...

event_emitter.on(\         


        

Answer 1

a monkey patch add onAny method to EventEmitter.

it is useful to be able to monitor only events of one problem.

var EventEmitter=require('events')
var origemit=EventEmitter.prototype.emit;
Object.assign( EventEmitter.prototype, {
  emit:function(){
    if(this._onAnyListeners){
        this._onAnyListeners.forEach((listener)=>listener.apply(this,arguments))
    }
    return origemit.apply(this,arguments)
  },
  onAny:function(func){
    if(typeof func !== 'function'){
      throw new Error('Invalid type');
    }
    if(!this._onAnyListeners)this._onAnyListeners=[];
    this._onAnyListeners.push(func);
  },
  removeOnAny:function(func){
    const index = this._onAnyListeners.indexOf(func);
    if(index === -1){
      return;
    }
    this._onAnyListeners.splice(index,1);
  }
});
// usage example
//gzip.onAny(function(a){console.log(a)})