framework/js/dist-typings/common/utils/mixin.d.ts

/**
 * The `mixin` utility assigns the properties of a set of 'mixin' objects to
 * the prototype of a parent object.
 *
 * @example
 * class MyClass extends mixin(ExistingClass, evented, etc) {}
 *
 * @param {object} Parent The class to extend the new class from.
 * @param {Record<string, any>[]} mixins The objects to mix in.
 * @return {object} A new class that extends Parent and contains the mixins.
 */
export default function mixin(Parent: object, ...mixins: Record<string, any>[]): object;