cal.pub0.org/components/ui/Button.tsx

export default function Button(props) {
  return (
    <button type="submit" className="btn btn-primary dark:btn-white">
      {!props.loading && props.children}
      {props.loading && (
        <svg
          className="animate-spin mx-4 h-5 w-5 text-white"
          xmlns="http://www.w3.org/2000/svg"
          fill="none"
          viewBox="0 0 24 24">
          <circle
            className="opacity-25"
            cx="12"
            cy="12"
            r="10"
            stroke="currentColor"
            strokeWidth="4"></circle>
          <path
            className="opacity-75"
            fill="currentColor"
            d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4zm2 5.291A7.962 7.962 0 014 12H0c0 3.042 1.135 5.824 3 7.938l3-2.647z"></path>
        </svg>
      )}
    </button>
  );
}