@ckeditor/ckeditor5-utils/src/mix.js

Miscellaneous utilities used by CKEditor 5.

/**
 * @license Copyright (c) 2003-2025, CKSource Holding sp. z o.o. All rights reserved.
 * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-licensing-options
 */
/**
 * @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.
 *
 * @deprecated Use mixin pattern, see: https://www.typescriptlang.org/docs/handbook/mixins.html.
 * @param baseClass Class which prototype will be extended.
 * @param mixins Objects from which to get properties.
 */
export default function mix(baseClass, ...mixins) {
    mixins.forEach(mixin => {
        const propertyNames = Object.getOwnPropertyNames(mixin);
        const propertySymbols = Object.getOwnPropertySymbols(mixin);
        propertyNames.concat(propertySymbols).forEach(key => {
            if (key in baseClass.prototype) {
                return;
            }
            if (typeof mixin == 'function' && (key == 'length' || key == 'name' || key == 'prototype')) {
                return;
            }
            const sourceDescriptor = Object.getOwnPropertyDescriptor(mixin, key);
            sourceDescriptor.enumerable = false;
            Object.defineProperty(baseClass.prototype, key, sourceDescriptor);
        });
    });
}