ckeditor/ckeditor5-utils

/**
 * @license Copyright (c) 2003-2020, CKSource - Frederico Knabben. All rights reserved.
 * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
 */

/**
 * @module utils/mix
 */

/**
 * Copies enumerable properties and symbols from the objects given as 2nd+ parameters to the
 * prototype of first object (a constructor).
 *
 *        class Editor {
 *            ...
 *        }
 *
 *        const SomeMixin = {
 *            a() {
 *                return 'a';
 *            }
 *        };
 *
 *        mix( Editor, SomeMixin, ... );
 *
 *        new Editor().a(); // -> 'a'
 *
 * Note: Properties which already exist in the base class will not be overriden.
 *
 * @param {Function} [baseClass] Class which prototype will be extended.
 * @param {Object} [...mixins] Objects from which to get properties.
 */
export default function mix( baseClass, ...mixins ) {
    mixins.forEach( mixin => {
        Object.getOwnPropertyNames( mixin ).concat( Object.getOwnPropertySymbols( mixin ) )
            .forEach( key => {
                if ( key in baseClass.prototype ) {
                    return;
                }

                const sourceDescriptor = Object.getOwnPropertyDescriptor( mixin, key );
                sourceDescriptor.enumerable = false;

                Object.defineProperty( baseClass.prototype, key, sourceDescriptor );
            } );
    } );
}