text: import invariant from 'invariant';
  import { isEmpty, isFunction, isString, conformsTo } from 'lodash';
  
  import checkStore from './checkStore';
  import { DAEMON, ONCE_TILL_UNMOUNT, RESTART_ON_REMOUNT } from './constants';
  
  const allowedModes = [RESTART_ON_REMOUNT, DAEMON, ONCE_TILL_UNMOUNT];
  
  const checkKey = (key) =>
    invariant(
      isString(key) && !isEmpty(key),
      '(app/utils...) injectSaga: Expected `key` to be a non empty string',
    );
  
  const checkDescriptor = (descriptor) => {
    const shape = {
      saga: isFunction,
      mode: (mode) => isString(mode) && allowedModes.includes(mode),
    };
    invariant(
      conformsTo(descriptor, shape),
      '(app/utils...) injectSaga: Expected a valid saga descriptor',
    );
  };
  
  export function injectSagaFactory(store, isValid) {
    return function injectSaga(key, descriptor = {}, args) {
      if (!isValid) checkStore(store);
  
      const newDescriptor = {
        ...descriptor,
        mode: descriptor.mode || DAEMON,
      };
      const { saga, mode } = newDescriptor;
  
      checkKey(key);
      checkDescriptor(newDescriptor);
  
      let hasSaga = Reflect.has(store.injectedSagas, key);
  
      if (process.env.NODE_ENV !== 'production') {
        const oldDescriptor = store.injectedSagas[key];
        // enable hot reloading of daemon and once-till-unmount sagas
        if (hasSaga && oldDescriptor.saga !== saga) {
          oldDescriptor.task.cancel();
          hasSaga = false;
        }
      }
  
      if (
        !hasSaga ||
        (hasSaga && mode !== DAEMON && mode !== ONCE_TILL_UNMOUNT)
      ) {
        /* eslint-disable no-param-reassign */
        store.injectedSagas[key] = {
          ...newDescriptor,
          task: store.runSaga(saga, args),
        };
        /* eslint-enable no-param-reassign */
      }
    };
  }
  
  export function ejectSagaFactory(store, isValid) {
    return function ejectSaga(key) {
      if (!isValid) checkStore(store);
  
      checkKey(key);
  
      if (Reflect.has(store.injectedSagas, key)) {
        const descriptor = store.injectedSagas[key];
        if (descriptor.mode && descriptor.mode !== DAEMON) {
          descriptor.task.cancel();
          // Clean up in production; in development we need `descriptor.saga` for hot reloading
          if (process.env.NODE_ENV === 'production') {
            // Need some value to be able to detect `ONCE_TILL_UNMOUNT` sagas in `injectSaga`
            store.injectedSagas[key] = 'done'; // eslint-disable-line no-param-reassign
          }
        }
      }
    };
  }
  
  export default function getInjectors(store) {
    checkStore(store);
  
    return {
      injectSaga: injectSagaFactory(store, true),
      ejectSaga: ejectSagaFactory(store, true),
    };
  }
  