Method extend

packages/@ember/object/core.ts:718–722

(...mixins: any[])

    ...mixins: M
  ): Readonly<Statics> & EmberClassConstructor<Instance> & MergeArray<M>;
  static extend(...mixins: any[]) {
    let Class = class extends this {};
    reopen.apply(Class.PrototypeMixin, mixins);
    return Class;
  }

  /**
    Creates an instance of a class. Accepts either no arguments, or an object