class Util {

    inject() {
        Element.prototype.remove = function (removeClassName) {
            this.classList.remove(removeClassName);
        }
        Element.prototype.add = function (addClassName) {
            this.classList.add(addClassName);
        }
    }

    click(className,callback) {
        $(className).onclick = () => {
            callback()
        }
    }

    $(className) {
        return document.querySelector(className)
    }

    _(className) {
        return document.querySelectorAll(className)
    }
}

var { $, _, click, inject } = new Util()

inject()