componentDidMount(){
      window.addEventListener('scroll', this.checkIfBottom());
    }

    componentWillUnmount() {
      window.removeEventListener('scroll', this.checkIfBottom());
    }

    checkIfBottom(){
      var thatElement = $('#repereBottom')
      var pos = thatElement.offset(),
      wX = $(window).scrollLeft(), wY = $(window).scrollTop(),
      wH = $(window).height(), wW = $(window).width(),
      oH = thatElement.outerHeight(), oW = thatElement.outerWidth();
      if (pos.left >= wX && pos.top >= wY && oW + pos.left <= wX + wW && oH + pos.top <= wY + wH ){
        //ET ICI TU FAIS TON STATE POUR LA PAGE
      }
    }