Sagaexample.js

import { takeLatest } from 'redux-saga';
import { take, actionChannel, select, call, put } from 'redux-saga/effects';
import authorizedFetch from 'common/utils/fetch/authorizedFetchSaga';
import { getAdAccount } from 'facebook/Campaigns/Manage/reducer/campaign';
import { getAdsets } from 'facebook/Campaigns/Manage/reducer/adsets';
import { FETCH_ADSETS_SUCCESS } from 'facebook/Campaigns/Manage/actions/adsets';
import { FETCH_CAMPAIGN_SUCCESS } from 'facebook/Campaigns/Manage/actions/campaign';
import {
  FETCH_TARGETING_INFO,
  createFetchTargetingInfoSuccess,
  createFetchTargetingInfoError,
} from '../actions';

export function *fetchTargetingInfo() {
  const [adAccount, adsets] = [
    yield select(getAdAccount),
    yield select(getAdsets),
  ];

  const specs = adsets.map(adset => adset.targeting);

  function *handleSuccess(result) {
    const adsetIdMap =
      result.specs
      .reduce((prev, curr, index) => ({
        ...prev,
        [adsets[index].id]: curr,
      }), {});

    yield put(
      createFetchTargetingInfoSuccess(adsetIdMap)
    );
  }

  yield call(
    authorizedFetch, [
      `adAccounts/${adAccount.id}/targetinginfo`, {
        method: 'POST',
        body: JSON.stringify({
          params: 'sentence,reach,bid',
          specs,
        }),
      },
    ],
    error => put(createFetchTargetingInfoError(error)),
    result => call(handleSuccess, result)
  );
}

export default function *() {
  const channel = yield actionChannel(FETCH_TARGETING_INFO);

  yield [ // wait for these
    take(FETCH_CAMPAIGN_SUCCESS),
    take(FETCH_ADSETS_SUCCESS),
  ];

  yield takeLatest(channel, fetchTargetingInfo);
}