Question

我正在构建一个应用程序，其中我有一些由更改器更改的状态。消费代码不应直接访问状态，而只能通过咖喱对变体进行按摩，从而使使用代码只需要调用部分应用的函数即可。

因此，而不是消费者调用：

setCount(state: State, firstArg: number, secondArg: number);

消费者应调用：

setCount(firstArg: number, secondArg: number)

为此，我有以下内容：

  interface State {
    count: number;
  }

  const state: State = {
    count: 0
  };

  interface IMutators {
    setCount: (state: State, firstArg: number, secondArg: number) => Partial<State>;
  }

  const mutators: IMutators = {
    setCount: (state: State, firstArg: number, secondArg: number) => ({
      count: state.count + x + y
    })
  };

  type RemoveStateParam<T extends any[]> = ((...x: T) => {}) extends ((
    h: State,
    ...t: infer R
  ) => {})
    ? R
    : never;

  type MutatorsWithoutState<M> = {
    [P in keyof M]: M[P] extends (...args: any[]) => any
      ? (...args: RemoveStateParam<Parameters<M[P]>>) => Partial<State>
      : never
  };

  type MutatorsInterface = MutatorsWithoutState<IMutators>;

  interface Context {
    mutators: MutatorsInterface;
  }

  const buildInterfaceFromImplementation = (
    mutators: IMutators,
    state: State
  ): MutatorsInterface => {
    const newObj = {};
    Object.keys(mutators).forEach(k => {
      const mutator = mutators[k];
      const curried = _.curry(mutator, 1);
      const interfaceCompliantMutator = curried(state);
      newObj[k] = interfaceCompliantMutator;
    });

    return newObj as MutatorsInterface;
  };

  const context: Context = {
    mutators: buildInterfaceFromImplementation(mutators, state)
  };

  context.mutators.setCount(1, 2);

我想改进的是buildInterfaceFromImplementation方法：

const newObj = {};
Object.keys(mutators).forEach(k => {
    const mutator = mutators[k];
    ...
});

 return newObj as MutatorsInterface;

是否有某种方法可以避免在最后一行使用演员表？我想像这样输入newObj：

const newObj: MutatorsInterface = {}; // This obviously won't work

逐步建立对象以满足类型

0 个答案: