#facebook-web-browser-messenger-export-toolkit.js

const CSS_SELECTOR = {
    displayed_chat: ".x78zum5.xdt5ytf.x1iyjqo2.x6ikm8r.x1odjw0f.xish69e.x16o0dkt", 
    message_block: "div.x78zum5.xdt5ytf.x1n2onr6[role]"
  }
  function scrollingToCheckPast( docHook = CSS_SELECTOR.displayed_chat ){
    document.querySelectorAll( // szuka WSZYSTKICH
      docHook // selektor CSS ()
    )[ 1 ].scrollTo(0,0) // scrolling do góry, wtedy ładuje
  }
  function getOutput( docHook = CSS_SELECTOR.message_block ){
    const DOM_COLLECTION = document.querySelectorAll( docHook );
    const ARRAY_LIST = Array.from( DOM_COLLECTION );
    var raw_output = ARRAY_LIST.filter(
      ( item )=>item.classList.length==3
    );
    //for(var message of raw_output)
    raw_output = raw_output.map(
      ( record )=>Array.from(
        record.querySelectorAll("span")
      ).map(
        ( txtBox )=>txtBox.innerText
      )
    );
    return raw_output;
    //Array.from(output[8].querySelectorAll("span")).map((x)=>x.innerText)
  }
  // testowane na chrome, dotyczy chatu po otwarciu "otwórz w messengerze"
  
  //var OUTPUT = []; //
  //var previousOutputLength = 0; // do sprawdzania czy ładuje nowe
  // testowane na chrome, dotyczy chatu po otwarciu "otwórz w messengerze"
  
  //var OUTPUT = []; //
  //var previousOutputLength = 0; // do sprawdzania czy ładuje nowe
  
  var DYNKSOWNICA = null;
  
  DYNKSOWNICA={
    delay:3000, // 3000 ms
    intervalRef:null,
    get ON(){
      this.intervalRef=setInterval(
        ()=>{
          scrollingToCheckPast();
          this.OUTPUT=getOutput();
          var diffLen=this.OUTPUT.length-this.previousOutLen;
          var nowPtr=Date.now();
          this.outLenLogs[nowPtr-this.UNIXUSAT]=diffLen;
          console.table([
            "ITERATION:",
            Object.keys(this.outLenLogs).length, 
            nowPtr-this.UNIXUSAT, 
            diffLen,
          ]);
          //console.log(this.PRINT);
          this.previousOutLen=this.OUTPUT.length;
        },
        this.delay
      );
    },
    get OFF(){
      clearInterval(this.intervalRef);
    },
    get PRINT(){
      console.log(JSON.stringify(this.OUTPUT, null, " "));
      return JSON.stringify(this.OUTPUT, null, " ");
    },
    UNIXUSAT:Date.now(),
    OUTPUT:[],
    previousOutLen:0,
    outLenLogs:null
  }

  DYNKSOWNICA.outLenLogs = {UNIXUSAT:DYNKSOWNICA.UNIXUSAT}