zoukankan      html  css  js  c++  java
  • [React Router] Create a ProtectedRoute Component in React Router (setState callback to force update)

    In this lesson we'll create a protected route just for logged in users. We'll combine a Route with a render prop and use a loggedIn prop to determine if the route should be allowed to be accessed. Finally we'll use nav state to preserve the location the user visited and redirect them back to the protected route once they login.

    1. Create a ProtectedRoute is nothing but just a react component render a Route component:

    • check the 'loggedIn' props, if true, then using render prop to render the component normally.
    • If 'loggedIn' props is false, then use 'Redirect' component to redirect to Home page. also pass the route state.
    const ProtectedRoute = ({ component: Comp, loggedIn, path, ...rest }) => {
      return (
        <Route
          path={path}
          {...rest}
          render={(props) => {
            return loggedIn ? (
              <Comp {...props} />
            ) : (
              <Redirect
                to={{
                  pathname: "/",
                  state: {
                    prevLocation: path,
                    error: "You need to login first!",
                  },
                }}
              />
            );
          }}
        />
      );
    };

    2. When the login button is clicked, we want to force udpate the state using callback in setState:

        this.setState(
          {
            loggedIn: true,
          },
          () => {
            this.props.history.push(prevLocation || "/");
          },
        );
      };

    setState() does not always immediately update the component. It may batch or defer the update until later. This makes reading this.state right after calling setState() a potential pitfall. Instead, use componentDidUpdate or a setState callback (setState(updater, callback)), either of which are guaranteed to fire after the update has been applied. If you need to set the state based on the previous state, read about the updater argument below. Link

  • 相关阅读:
    Freemaker:操作集合
    win10:在关闭防火墙下如何屏蔽特定端口
    win10:家庭版开启组策略
    oracle:10g下载地址(转载)
    mybatis:延迟加载时不要在get/set方法上面添加final关键字(原创)
    mybatis:在springboot中的配置
    mybatis:访问静态变量或方法
    maven:手动安装JAR到本地仓库
    datatables日常使用集合
    python 装饰器
  • 原文地址:https://www.cnblogs.com/Answer1215/p/8746827.html
Copyright © 2011-2022 走看看