Liferay.Loader.define('document-library-preview-image$redux@4.0.5/src/combineReducers', ['module', 'exports', 'require'], function (module, exports, require) {
  var define = undefined;
  var global = window;
  {
    import ActionTypes from './utils/actionTypes';
    import warning from './utils/warning';
    import isPlainObject from './utils/isPlainObject';

    function getUndefinedStateErrorMessage(key, action) {
      const actionType = action && action.type;
      const actionDescription = actionType && `action "${String(actionType)}"` || 'an action';

      return `Given ${actionDescription}, reducer "${key}" returned undefined. ` + `To ignore an action, you must explicitly return the previous state. ` + `If you want this reducer to hold no value, you can return null instead of undefined.`;
    }

    function getUnexpectedStateShapeWarningMessage(inputState, reducers, action, unexpectedKeyCache) {
      const reducerKeys = Object.keys(reducers);
      const argumentName = action && action.type === ActionTypes.INIT ? 'preloadedState argument passed to createStore' : 'previous state received by the reducer';

      if (reducerKeys.length === 0) {
        return 'Store does not have a valid reducer. Make sure the argument passed ' + 'to combineReducers is an object whose values are reducers.';
      }

      if (!isPlainObject(inputState)) {
        return `The ${argumentName} has unexpected type of "` + {}.toString.call(inputState).match(/\s([a-z|A-Z]+)/)[1] + `". Expected argument to be an object with the following ` + `keys: "${reducerKeys.join('", "')}"`;
      }

      const unexpectedKeys = Object.keys(inputState).filter(key => !reducers.hasOwnProperty(key) && !unexpectedKeyCache[key]);

      unexpectedKeys.forEach(key => {
        unexpectedKeyCache[key] = true;
      });

      if (action && action.type === ActionTypes.REPLACE) return;

      if (unexpectedKeys.length > 0) {
        return `Unexpected ${unexpectedKeys.length > 1 ? 'keys' : 'key'} ` + `"${unexpectedKeys.join('", "')}" found in ${argumentName}. ` + `Expected to find one of the known reducer keys instead: ` + `"${reducerKeys.join('", "')}". Unexpected keys will be ignored.`;
      }
    }

    function assertReducerShape(reducers) {
      Object.keys(reducers).forEach(key => {
        const reducer = reducers[key];
        const initialState = reducer(undefined, { type: ActionTypes.INIT });

        if (typeof initialState === 'undefined') {
          throw new Error(`Reducer "${key}" returned undefined during initialization. ` + `If the state passed to the reducer is undefined, you must ` + `explicitly return the initial state. The initial state may ` + `not be undefined. If you don't want to set a value for this reducer, ` + `you can use null instead of undefined.`);
        }

        if (typeof reducer(undefined, {
          type: ActionTypes.PROBE_UNKNOWN_ACTION()
        }) === 'undefined') {
          throw new Error(`Reducer "${key}" returned undefined when probed with a random type. ` + `Don't try to handle ${ActionTypes.INIT} or other actions in "redux/*" ` + `namespace. They are considered private. Instead, you must return the ` + `current state for any unknown actions, unless it is undefined, ` + `in which case you must return the initial state, regardless of the ` + `action type. The initial state may not be undefined, but can be null.`);
        }
      });
    }

    /**
     * Turns an object whose values are different reducer functions, into a single
     * reducer function. It will call every child reducer, and gather their results
     * into a single state object, whose keys correspond to the keys of the passed
     * reducer functions.
     *
     * @param {Object} reducers An object whose values correspond to different
     * reducer functions that need to be combined into one. One handy way to obtain
     * it is to use ES6 `import * as reducers` syntax. The reducers may never return
     * undefined for any action. Instead, they should return their initial state
     * if the state passed to them was undefined, and the current state for any
     * unrecognized action.
     *
     * @returns {Function} A reducer function that invokes every reducer inside the
     * passed object, and builds a state object with the same shape.
     */
    export default function combineReducers(reducers) {
      const reducerKeys = Object.keys(reducers);
      const finalReducers = {};
      for (let i = 0; i < reducerKeys.length; i++) {
        const key = reducerKeys[i];

        if (typeof reducers[key] === 'function') {
          finalReducers[key] = reducers[key];
        }
      }
      const finalReducerKeys = Object.keys(finalReducers);

      // This is used to make sure we don't warn about the same
      // keys multiple times.


      let shapeAssertionError;
      try {
        assertReducerShape(finalReducers);
      } catch (e) {
        shapeAssertionError = e;
      }

      return function combination(state = {}, action) {
        if (shapeAssertionError) {
          throw shapeAssertionError;
        }

        let hasChanged = false;
        const nextState = {};
        for (let i = 0; i < finalReducerKeys.length; i++) {
          const key = finalReducerKeys[i];
          const reducer = finalReducers[key];
          const previousStateForKey = state[key];
          const nextStateForKey = reducer(previousStateForKey, action);
          if (typeof nextStateForKey === 'undefined') {
            const errorMessage = getUndefinedStateErrorMessage(key, action);
            throw new Error(errorMessage);
          }
          nextState[key] = nextStateForKey;
          hasChanged = hasChanged || nextStateForKey !== previousStateForKey;
        }
        hasChanged = hasChanged || finalReducerKeys.length !== Object.keys(state).length;
        return hasChanged ? nextState : state;
      };
    }
  }
});
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