Create dynamic lists in React

class App extends React.Component{  state = {    lists : {      'list-1' : 'PHP',      'list-2' : 'Wordpress'    }  }    addList = (list) => {      var timestamp = (new Date()).getTime();      this.state.lists['list-' + timestamp ] = list;      this.setState({ lists : this.state.lists });     }     removeList = (listKey) => {      delete this.state.lists[listKey];      this.setState({ lists : this.state.lists });     }     render() {      return (        <div className="component-wrapper">          <ItemList lists={this.state.lists} removeList={this.removeList}/>          <AddListForm addList={this.addList} />        </div>       );      }     }     class ItemList extends React.Component{      render () {        return (          <div className="container">            <ul className="list-group text-center">              {                Object.keys(this.props.lists).map(function(key) {                  return <li className="list-group-item list-group-item-info">{this.props.lists[key]} <span onClick={()=>this.props.removeList(key)}>X</span></li>                }.bind(this))              }            </ul>           </div>          );        }      }      class AddListForm extends React.Component{        createList = (e) => {          e.preventDefault();          var list = this.refs.listName.value;          if(list.length > 0) {            this.props.addList(list);          }          this.refs.listForm.reset();        }        render = () => {          return(            <form className="form-inline" ref="listForm" onSubmit={this.createList}>              <div className="form-group">                <label for="listItem">                  List Name                  <input type="text" id="listItem" className="form-control" placeholder="e.x.lemmon" ref="listName" />                </label>              </div>              <button type="submit" className="btn btn-primary">Add List</button>            </form>          )        }      }      React.render(        <App />,        document.getElementById('app')      );