更新的打字稿 - 在组合减速器功能 TS2344 上接收错误

Question

我仍在努力理解 TypeScript，但我不确定这在这里试图告诉我什么。任何帮助将不胜感激。

此代码正在接收减速器对象的对象。在编译我的 React/Ionic 项目时，我现在在更新底层库后收到以下错误：

.../src/data/combineReducers.ts(3,47) 中的 TypeScript 错误：

• 类型“R[K]”不满足约束“(...args: any) => any”。
• 类型 'R[keyof R]' 不能分配给类型 '(...args: any) => any'。
• 键入'R[字符串] | R[号码] | R[symbol]' 不可分配给类型 '(...args: any) => any'。
• 类型 'R[string]' 不能分配给类型 '(...args: any) => any'。 TS2344

[react-scripts]     1 | export function combineReducers<R extends any>(reducers: R) {
[react-scripts]     2 |   type keys = keyof typeof reducers;
[react-scripts]   > 3 |   type returnType = { [K in keys]: ReturnType<typeof reducers[K]> }
[react-scripts]       |                                               ^
[react-scripts]     4 |   const combinedReducer = (state: any, action: any) => {
[react-scripts]     5 |     const newState: returnType = {} as any;
[react-scripts]     6 |     const keys = Object.keys(reducers);

export function combineReducers<R extends any>(reducers: R) {
  type keys = keyof typeof reducers;
  type returnType = { [K in keys]: ReturnType<typeof reducers[K]> }
  const combinedReducer = (state: any, action: any) => {
    const newState: returnType = {} as any;
    const keys = Object.keys(reducers);
    keys.forEach(key => {
      const result = reducers[key](state[key], action);
      newState[key as keys] = result || state[key];
    });
    return newState;
  }
  return combinedReducer;
};

Answer 1

npm i typescript@3.8.3后问题解决

Answer 2

另一个完整的解决方案在这里：

function combineReducers(reducers: R)

来源：https://github.com/ionic-team/ionic-react-conference-app/issues/50