for (var i = 0; i < this.buttonClick.length; i++) {

    this.buttonClick.onclick[i] = () => {

        if (this.modalBlock.classList.contains(this.currentClass + '--active-js') == false) {
            this.modalBlock.classList.add(this.currentClass + '--active-js');
            this.body.style.overflow = 'hidden';
        }
    }

}