Disable CF7 submit button on submit

<script>
    const wpcf7Elm = document.querySelector( '.wpcf7 form' );
    const $formBtn = wpcf7Elm.querySelector( '.wpcf7-submit');
    const originalLabel = $formBtn.value;
    wpcf7Elm.addEventListener('submit', function(e){
        $formBtn.value = "Sending...";
        $formBtn.disabled = true;
    });
    wpcf7Elm.addEventListener( 'wpcf7submit', function( event ) {
        $formBtn.disabled = false;
        $formBtn.value = originalLabel;
    }, false );
</script>