React -在初始加载时，我的状态数组只保存最后一个元素

constructor(props) {
  super(props);
  this.state = {
    elements: []
  };
}

render() {
  const { elements } = this.state;
  const lastElement = elements.length > 0 ? elements[elements.length - 1] : null;

  return (
    <div>
      Last Element: {lastElement}
    </div>
  );
}

componentDidMount() {
  // 假设从某个地方获取到了新元素
  const newElement = "New Element";

  this.setState(prevState => ({
    elements: [...prevState.elements, newElement]
  }));
}