javascript onClick replace user_meta from jquery.ajax

The thought is so as to add two values and the overall of the sum put it aside or replace it in user_meta with jquery.ajax.
That is the code, but it surely provides me an error within the console Uncaught ReferenceError: ‘whole’ just isn’t outlined

Please, Any assistance is appreciated!

My Button

<a href="" onclick="CounterTrav()" id="btnTraPack"></a>

javascript

<script>
//This sum the tow values i get from a click on and works OK!

const clicksContainer = doc.querySelector('.clicksContainer');
const totalEl = doc.createElement('span');
clicksContainer.appendChild(totalEl);

clicksContainer.addEventListener('click on', operate(e) {
  if (!e.goal.classList.comprises('clicksContainer')) {
    const shareCLick = doc.querySelectorAll('.resultTraveler');
    let whole = 0;
    shareCLick.forEach(merchandise => {
      whole += parseInt(merchandise.innerText, 10)
    totalEl.innerHTML = whole
    })
    console.log(whole);
  }
})

var clickCounterTrav = 0
operate CounterTrav() {
    
  clickCounterTrav += 1;
  doc.getElementById("resultTraveler").innerHTML = clickCounterTrav + " Travel Pack you have Shared!";
console.log(clickCounterTrav);

var CounterTrav_update = 'clickCounterTrav';
jQuery.ajax({
    url: '/wp-admin/admin-ajax.php',
        
        knowledge : {
            motion : 'CounterTrav_update', 
            CounterTrav_value : CounterTrav_value,
        },
        beforeSend: operate() {
               console.log('Updating Subject');
        },
        success : operate( response ) {
             console.log('Success');
        },
        
    });
}
</script>

// MY ISSUE START HERE
If I take advantage of

var CounterTrav_update = 'clickCounterTrav';

The results of the sum is Appropriate, and the user_meta is Replace OK!, BUT solely replace "clickCounterTrav"
Like Eg: The person onready have in user_meta 2 clicks storage, and in session2 click on only one time, then replace user_meta with 1 worth.

PHP

add_action( 'wp_ajax_CounterTrav_update', 'CounterTrav_update' );
add_action( 'wp_ajax_nopriv_CounterTrav_update', 'CounterTrav_update' ); // This strains it is as a result of we're utilizing AJAX on the FrontEnd.

operate CounterTrav_update(){
    if(empty($_REQUEST) || !isset($_REQUEST)) {
        ajaxStatus('error', 'Nothing to replace.');
    } else {
        strive {
            $person = wp_get_current_user();
            $CounterTrav_value = $_GET['CounterTrav_value'];
                update_user_meta( $user->ID, 'clickCounterTrav', $CounterTrav_value );
            
            die();
        } catch (Exception $e){
            echo 'Caught exception: ',  $e->getMessage(), "n";
        }
    }
}  

If I take advantage of

var CounterTrav_update = 'whole';

Then the Sum result’s Nan and in Console error is: Uncaught ReferenceError: whole just isn’t outlined