PROJECT_HIPSTAGRAM/src/redux/saga/subscribe/index.js

import {
  actionChangeSubscribe,
  actionGetFollowers,
  actionGetFollowing,
} from '../../../actions/query/subscribeQuery'
import { promiseWorker } from '../promise'
import { put, takeEvery, call, select } from 'redux-saga/effects'
import {
  actionChangeFollowingType,
  actionChangeFollowersType,
} from '../../../actions/types/subscribeTypes'
function* changeSubscribeWorker({ followId, checkFollowId }) {
  const {
    myData: {
      aboutMe: { _id, following },
    },
  } = yield select()

  const oldFollowing = checkFollowId
    ? {
        _id,
        following: [
          ...(following || [])
            .filter((item) => item._id !== followId)
            .map(({ _id }) => ({ _id })),
        ],
      }
    : {
        _id,
        following: [
          ...(following || []).map(({ _id }) => ({ _id })),
          { _id: followId },
        ],
      }

  yield call(promiseWorker, actionChangeSubscribe(oldFollowing))

  const updateUserFollowers = yield call(
    promiseWorker,
    actionGetFollowers(followId),
  )

  const updateMyFollowing = yield call(promiseWorker, actionGetFollowing(_id))

  if (updateMyFollowing)
    yield put(actionChangeFollowingType(updateMyFollowing?.following))
  if (updateUserFollowers)
    yield put(actionChangeFollowersType(updateUserFollowers?.followers))
}
export function* changeSubscribeWatcher() {
  yield takeEvery('CHANGE_SUBSCRIBE', changeSubscribeWorker)
}