'@ redux-saga / core'中SagaIterator的用途是什么

Question

[函数发生器中SagaIterator的用途是什么？

import { SagaIterator } from '@redux-saga/core'

function* getCountry(action: ReturnType<typeof actions.country.request>) : SagaIterator {
    try {       
        const selectedCountry = (state: models.InitialStateTypes) => state.selectedCountryInitial        
        const data = yield select(selectedCountry)       
        const response: AxiosResponse<models.CountryInitialResponse> = yield call(
            axios.get , 
            'https://covid19.mathdro.id/api/countries/${data}' , 
            { 
                params: action.payload 
            }
        );
        yield put(actions.country.success(response.data))
    } catch (error) {
        yield put(actions.country.failure(error))
    }
}

Answer 1

查看源代码，我们可以看到作者的评论：

/**
 * Annotate return type of generators with `SagaIterator` to get strict
 * type-checking of yielded effects.
 */
export type SagaIterator = IterableIterator<StrictEffect>

以及快速浏览StrictEffect的定义：

export type StrictEffect<T = any> = SimpleEffect<T, any> | StrictCombinatorEffect<T>

export interface StrictCombinatorEffect<T> extends CombinatorEffect<T, StrictEffect<T>> {}

export interface SimpleEffect<T, P> {
  '@@redux-saga/IO': true
  combinator: false
  type: T
  payload: P
}

所以它说的是，生成器会产生redux-saga效果，例如放置，调用，选择等。这意味着，如果尝试在生成器中生成其他内容，则应该从Typescript中得到编译错误