Source: core/reducers/createReducer.es.js

/**
 * Copyright (c) 2000-present Liferay, Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
 * details.
 */

export const createReducer = (reducers, config) => (state, action) =>
	reducers.reduce((prevState, reducer) => {
		const nextProperties = reducer(prevState, action, config);

		if (prevState === nextProperties) {
			return nextProperties;
		}

		return {
			...prevState,
			...nextProperties,
		};
	}, state);