Js Extended History Object

extended.history.js

/*
  Author: Hasan Delibaş
  Under MIT License
*/

// CustomEvent
(function () {
  if ( typeof window.CustomEvent === "function" ) return false;
  function CustomEvent ( event, params ) {
    params = params || { bubbles: false, cancelable: false, detail: null };
    var evt = document.createEvent( 'CustomEvent' );
    evt.initCustomEvent( event, params.bubbles, params.cancelable, params.detail );
    return evt;
   }
  window.CustomEvent = CustomEvent;
})();

(function(){
  let stateSymbol = "__state__index__";
  history.stateIndex =-1;
  history.states=[];
  let pushState = history.pushState;
  function add(data,title,url){
    if(data==null) data={};
    if(typeof data!="object") data={data:data};
    data[stateSymbol] = (history.stateIndex+1);
    history.states.splice(history.stateIndex+1,0,[data,title,url])
    history.states.splice(history.stateIndex+2)
    history.stateIndex++;
  }
  history.pushState =function(data,title,url=null){
    add(data,title,url);
    pushState.bind(history)(data,title,url);
  }
  addEventListener("popstate",function(e){
    var eventObject= {};
    var newStateIndex =  e.state!=null ? e.state[stateSymbol] : -1;
    eventObject.from = history.states[history.stateIndex];
    eventObject.to   = newStateIndex>-1 ? history.states[newStateIndex] : null;
    eventObject.side = history.stateIndex>newStateIndex ? "back" : "forward"; 
    if( newStateIndex > -1 && !(newStateIndex in history.states) ){
      add(history.state,"",window.location.href);
    }
    window.dispatchEvent(new CustomEvent("historyChange", {detail: eventObject} ))
    history.stateIndex = e.state!=null ? e.state[stateSymbol] : -1;
  });
})();

/******************************************************************

                            Using
    history.states
    history.stateIndex
    
    addEventListener("historyChange",function(e))

******************************************************************/


/**
  * @param e.detail.from [data,title,url]
  * @param e.detail.to   [data,title,url]
  * @param e.detail.side "back" | "forward"
  */
addEventListener("historyChange",function(e){
  var from = e.detail.from; // [ data , title , url ]
  var to   = e.detail.to;   // [ data , title , url ]
  var side = e.detail.side; // "back" | "forward"
  console.log( `You changed history. Side is ${e.detail.side}.\nFrom:${e.detail.from[2]}\nTo:${e.detail.to[2]}`)
})

history.pushState("1", "DENEME-TEST" ,"?1");
history.pushState("2", "DENEME-TEST" ,"?2");
// list of history states
console.log( history.states )
/*
[
  [ {...} ,  "DENEME-TEST" ,"?1" ]
  [ {...} ,  "DENEME-TEST" ,"?2" ]
]
*/
// get history current state index
console.log( history.stateIndex )
/*
1
*/