Can‘t perform a React state update on an unmounted component. This is a no-op, but it indicates a memory leak in your application. To fix, cancel all subscriptions and asynchronous tasks in the componentWillUnmount method.

解决：

在componentWillUnmount里面增加 this.setState = () => false;   意思是将this.setState设置为false

例如：

  componentWillUnmount() {
     this.setState = () => false;
  }

　　出现原因：某些时候请求接口数据加载比较慢，这时候setState还未完成，用户切换了组件或者切换页面时候，组件卸载了，而这个setState动作还在持续，所以react会出现警告

Can't perform a React state update on an unmounted component. This is a no-op, but it indicates a memory leak in your application. To fix, cancel all subscriptions and asynchronous tasks in the