JavaScript Document queryCommandSupported() Method

const flg = document.queryCommandSupported("SelectAll");
console.log("SelectAll supported:", flg);

if (flg) {
  console.log("Safe to consider SelectAll in this browser");
}

const hasApi = typeof document.queryCommandSupported === "function";
console.log("queryCommandSupported available:", hasApi);

if (hasApi) {
  console.log("bold supported:", document.queryCommandSupported("bold"));
} else {
  console.log("Use a modern editor / Clipboard API instead");
}

const names = ["bold", "SelectAll", "copy", "paste"];

names.forEach((name) => {
  const supported =
    typeof document.queryCommandSupported === "function"
      ? document.queryCommandSupported(name)
      : false;
  const enabled =
    typeof document.queryCommandEnabled === "function"
      ? document.queryCommandEnabled(name)
      : false;
  console.log(name + " → supported=" + supported + ", enabled=" + enabled);
});