反应上下文挂钩更新后如何触发功能

Question

我正在尝试在 React 的“上下文挂钩”更新后调用一个函数。尝试了以下代码：

const MyComponent = () => {
  [context] = useContext(MyContext);
  
  function updateContext():void {
    context = "someNewContext";
  }
  
  function anotherFunction():void {
    console.log("success!");
  }
  
  useEffect(() => {
    anotherFunction();
  }, [context]);
  
  return (
    <button onClick={updateContext}>update</button>
  );
}

export default MyComponent;

Answer 1

现在我知道出了什么问题...首先我需要一个带有 useState 的包装器，如下所示：

const App = () => {
  const [context, setContext] = useState("initial value");
  const value = { context, setContext };

  return (
    <MyContext.Provider value={value}>
      <MyComponent />
    </MyContext.Provider>
  );
};

然后在组件上：

const MyComponent = () => {
  {context, setContext} = useContext(MyContext);

  function updateContext():void {
    setContext("Some new context");
  }

  function anotherFunction():void {
    console.log("success!");
  }

  useEffect(() => {
    anotherFunction();
  }, [context]);

  return (
    <button onClick={() => {updateContext()}}>update</button>
  );
}

export default MyComponent;

反应上下文挂钩更新后如何触发功能

How trigger function after react context hook updated

reactjs

react-hooks

use-effect

use-context