containsCalls static method
Indicates whether the browser's storage contains any calls.
Implementation
static bool containsCalls() {
  for (var i = 0; i < web.window.localStorage.length; ++i) {
    final k = web.window.localStorage.key(i);
    if (k?.startsWith('call_') ?? false) {
      return true;
    }
  }
  return false;
}