var starRating = [...document.querySelectorAll('.starRating')].map(o => o.innerText).join('\n');

for (let x = 0; x <  starRating.length; x++){
  function Getrating() {
    $starNumber = "5";
    for($x=1;$x<=$starNumber;$x++) {
      $output .= '<i class="fa fa-star" aria-hidden="true"></i>';
    }
    if (strpos($starNumber,'.')) {
       $output .= '<i class="fa fa-star-half-o" aria-hidden="true">       </i>';
        $x++;
    }
    while ($x<=5) {
      $output .= '<i class="fa fa-star-o" aria-hidden="true"></i>';
      $x++;
    }
    return $output;

 }

   add_shortcode('starrating', 'Getrating');
}

<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" rel="stylesheet" />

//wordpress code
<div class="starRating">
  <?php the_field('rating'); ?> /
  <?php the_field('review_count'); ?>
</div>

//html code in inspector
<div class="starRating"> 3.2 /345 </div>

<div class="starRating"> 4 /4567 </div>

<div class="starRating"> 4.7 /987 </div>

<div class="starRating"> 2.7 /1210 </div>