Function updateStyle

life-cycle-callbacks/main.js:42–51

(elem)

customElements.define("custom-square", Square);

function updateStyle(elem) {
  const shadow = elem.shadowRoot;
  shadow.querySelector("style").textContent = `
    div {
      width: ${elem.getAttribute("size")}px;
      height: ${elem.getAttribute("size")}px;
      background-color: ${elem.getAttribute("color")};
    }
  `;
}

const add = document.querySelector(".add");
const update = document.querySelector(".update");