Reactjs 上下文值的提供程序不'；不变

我正在尝试在一个新的react+typescript示例项目中学习ContextAPI

我想管理区域设置/身份验证

我必须初始化我的上下文值（Typescript/eslint需要），特别是登录/注销函数，或者“App.tsx”中发生错误：“无法调用可能未定义的对象”

对，我试着将我的上下文初始化如下：

const AuthContext = React.createContext<ContextProps>({
    ...initialState,
    login: () => {
        throw new Error("login() not implemented yet");
    },
    logout: () => {
        throw new Error("logout() not implemented yet");
    }
 });

---

新的登录/注销定义似乎没有传递给AuthContext中的提供者。我很确定我错过了ContextAPI中的一个概念，并且我不理解其背后的逻辑。感谢您的建议。

您需要添加具有新上下文的提供者。React将在树上查找第一个上下文提供程序，如果没有，使用者将获得默认值

const App = () => {
  return (
  <Context.Language.Consumer>
    {({ locale, translation, switchLocale }) => (
       <Context.Auth.Provider>
          <Context.Auth.Consumer>
            {Auth => (
                <NavItem right>
                  {Auth.isLoggedIn ? (
                      <Button onClick={() => Auth.logout()}>
                        {translation.logout}
                      </Button>
                  ) : (
                      <Button onClick={() => Auth.login()}>
                        {translation.login}
                      </Button>
                  )}
                </NavItem>
            )}
        </Context.Auth.Consumer>
      <Context.Auth.Provider>
    )}
  </Context.Language.Consumer>

const-App=（）=>{
返回(
{（{locale，translation，switchLocale}）=>(
{Auth=>(
{Auth.isLoggedIn(
Auth.logout（）}>
{translation.logout}
) : (
Auth.login（）}>
{translation.login}
)}
)}
)}

))； };

// ./contexts/AuthContext.tsx
import React, {Component} from "react";

type ContextProps = {
  isLoggedIn: boolean;
  login: () => void;
  logout: () => void;
};

const initialState = { isLoggedIn: false };
type Props = {};
type State = {} & typeof initialState;

const AuthContext = React.createContext<ContextProps>({
  ...initialState,
  login: () => {
    throw new Error("login() not implemented yet");
  },
  logout: () => {
    throw new Error("logout() not implemented yet");
  }
});

class AuthProvider extends Component<Props, State> {
   readonly state = initialState;

  login = () => {
    this.setState({
      isLoggedIn: true
    });
  };

  logout = () => {
    this.setState({
      isLoggedIn: false
    });
  };

  render() {
    return (
      <AuthContext.Provider
        value={{...this.state, login: this.login, logout: this.logout}}
      >
        {this.props.children}
      </AuthContext.Provider>
    );
  }
}

export const Consumer = AuthContext.Consumer;
export const Provider = AuthProvider;

// ./contexts/index.js
import * as Auth from "./AuthContext";
import * as Language from "./LanguageContext";

export { Auth, Language };

const App = () => {
  return (
  <Context.Language.Consumer>
    {({ locale, translation, switchLocale }) => (
       <Context.Auth.Provider>
          <Context.Auth.Consumer>
            {Auth => (
                <NavItem right>
                  {Auth.isLoggedIn ? (
                      <Button onClick={() => Auth.logout()}>
                        {translation.logout}
                      </Button>
                  ) : (
                      <Button onClick={() => Auth.login()}>
                        {translation.login}
                      </Button>
                  )}
                </NavItem>
            )}
        </Context.Auth.Consumer>
      <Context.Auth.Provider>
    )}
  </Context.Language.Consumer>