Manipolare il content di un before

[techno]

non è nulla:

const btEye = document.querySelector(".bt-eye");
btEye.addEventListener("click", (e) => {
    e.preventDefault();

    const dataEye = e.target.getAttribute("data-eye");

    if (dataEye === "0") {        btEye.setAttribute("data-eye", "1");
        btEye.children.style.content = "\f070";
    } else {
        btEye.children.style.content = "\f06e";
    }

   e.stopImmediatePropagation();
});