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

import { useState } from 'react';

export default function Button(props) {
  return(
    <button type="submit" className="btn btn-primary">
      {!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>
  );
}