redux-saga-watch-actions/es/middleware.js

Easily create watchers to map actions to sagas

import invariant from 'tiny-invariant';
export const createCancelTask = tasks => key => {
  if (!tasks[key]) {
    return;
  }

  const task = tasks[key].task;

  if (!task) {
    return;
  }

  const result = task.cancel();
  delete tasks[key];
  return result;
};
export const createCancelAllTasks = (tasks, cancelTask) => () => Object.keys(tasks).map(key => cancelTask(key));
export const createInjectSaga = (tasks, cancelTask, runSaga) => function () {
  let _ref = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {},
      key = _ref.key,
      saga = _ref.saga,
      args = _ref.args;

  !key ? process.env.NODE_ENV !== "production" ? invariant(false, 'injectSaga expects a key option to identify this saga') : invariant(false) : void 0;
  !saga ? process.env.NODE_ENV !== "production" ? invariant(false, 'injectSaga expects a saga option to specify which saga to run') : invariant(false) : void 0;
  !(args === undefined || Array.isArray(args)) ? process.env.NODE_ENV !== "production" ? invariant(false, 'injectSaga expects args option to be undefined or an array of args') : invariant(false) : void 0;
  let task;
  let prevSaga;

  if (tasks[key]) {
    task = tasks[key].task;
    prevSaga = tasks[key].prevSaga;
  }

  if (task && prevSaga !== saga) {
    cancelTask(key);
    task = undefined;
  }

  const alreadyRunning = task && typeof task.isRunning === 'function' ? task.isRunning() : false;

  if (task === undefined || !alreadyRunning) {
    task = args ? runSaga(saga, args) : runSaga(saga);
    tasks[key] = {
      task,
      prevSaga: saga
    };
  }

  return task;
};

const createSagaMiddlewareHelpers = function createSagaMiddlewareHelpers(sagaMiddleware) {
  let tasks = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
  !(sagaMiddleware && typeof sagaMiddleware.run === 'function') ? process.env.NODE_ENV !== "production" ? invariant(false, 'createSagaMiddlewareHelpers expects a sagaMiddleware to include a run method') : invariant(false) : void 0;

  const runSaga = function runSaga() {
    return sagaMiddleware.run(...arguments);
  };

  const cancelTask = createCancelTask(tasks);
  const cancelAllTasks = createCancelAllTasks(tasks, cancelTask);
  const injectSaga = createInjectSaga(tasks, cancelTask, runSaga);
  return {
    cancelAllTasks,
    cancelTask,
    injectSaga,
    runSaga
  };
};

export default createSagaMiddlewareHelpers;