CustomElementRegistry: метод getName()

getName(constructor)

class MyParagraph extends HTMLElement {
  constructor() {
    let templateContent = document.getElementById("custom-paragraph").content;
    super() // returns element this scope
      .attachShadow({ mode: "open" }) // sets AND returns this.shadowRoot
      .append(templateContent.cloneNode(true));
  }
}

customElements.define("my-paragraph", MyParagraph);

// Return a reference to the my-paragraph constructor
customElements.getName(MyParagraph) === "my-paragraph";