constructor(props) {
    super(props);
    this.state = {
      isLoaded: this.props.isLoaded,
      menuMobile: true
    };
    // reference to the DOM node
    this.home = null;
    // reference to the animation
    this.tl = new TimelineLite({ paused: true });

    this.scrollToTop = this.scrollToTop.bind(this);
    this.openMenuMobile = this.openMenuMobile.bind(this);
    this.closeMenuMobile = this.closeMenuMobile.bind(this);
  }

<li ref={ li => this.home = li }>
                  <NavLink to={"/"} activeClassName="active" className="a-item">
                    <span>home</span>
                  </NavLink>
                </li>

Error: Cannot tween a null target.