CODE EXAMPLE FOR JAVASCRIPT

js listen websocket

function listen(fn){
  fn=fn||console.log
  let property=Object.getOwnPropertyDescriptor
  (MessageEvent.prototype,"data")
  const data=property.get
  function lookAtMessage(){ //to replace get function
    let socket=this.currentTarget instanceof WebSocket
    if(!socket){return data.call(this)}
    let msg=data.call(this)
    Object.defineProperty(this,"data",{value:msg}) //anti-loop
    fn({data:msg,socket:this.currentTarget,event:this})
    return msg
  }
  property.get=lookAtMessage
  Object.defineProperty
  (MessageEvent.prototype,"data",property)
}
listen( ({data})=>console.log(data) )