Gizle Göster butonu nasıl yapabilirim?

                        <nav class="alert alert-simple alert-primary alert-icon table-of-contents">
                        <span class="title title-sm title-line title-underline"><span><i class="d-icon-mode-list"></i> İçerik Listesi</span></span>
                            </nav>

class TableOfContents {
    constructor({ from: e, to: t }) {
        (this.fromElement = e), (this.toElement = t), (this.headingElements = this.fromElement.querySelectorAll("h1, h2, h3, h4, h5, h6")), (this.tocElement = document.createElement("div"));
    }
    getMostImportantHeadingLevel() {
        let e = 6;
        for (let t = 0; t < this.headingElements.length; t++) {
            let n = TableOfContents.getHeadingLevel(this.headingElements[t]);
            e = n < e ? n : e;
        }
        return e;
    }
    static generateId(e) {
        return e.textContent.replace(/\s+/g, "_");
    }
    static getHeadingLevel(e) {
        switch (e.tagName.toLowerCase()) {
            case "h1":
                return 1;
            case "h2":
                return 2;
            case "h3":
                return 3;
            case "h4":
                return 4;
            case "h5":
                return 5;
            case "h6":
                return 6;
            default:
                return 1;
        }
    }
    generateToc() {
        let e = this.getMostImportantHeadingLevel() - 1,
            t = this.tocElement;
        for (let n = 0; n < this.headingElements.length; n++) {
            let l = this.headingElements[n],
                a = TableOfContents.getHeadingLevel(l),
                r = a - e,
                o = document.createElement("a");
            if ((l.id || (l.id = TableOfContents.generateId(l)), (o.href = `#${l.id}`), (o.textContent = l.textContent), r > 0)) {
                for (let e = 0; e < r; e++) {
                    let e = document.createElement("ol"),
                        n = document.createElement("li");
                    e.appendChild(n), t.appendChild(e), (t = n);
                }
                t.appendChild(o);
            } else {
                for (let e = 0; e < -r; e++) t = t.parentNode.parentNode;
                let e = document.createElement("li");
                e.appendChild(o), t.parentNode.appendChild(e), (t = e);
            }
            e = a;
        }
        this.toElement.appendChild(this.tocElement.firstChild);
    }
}
document.addEventListener("DOMContentLoaded", () => new TableOfContents({ from: document.querySelector(".article"), to: document.querySelector(".table-of-contents") }).generateToc());