Comment imprimer le motif de diamant en javascript

<script type="text/javascript">

 for(let i=1; i<=4; i++){
           for( let b = 1; b<=(rows-i); b++)
           document.write("&nbsp;");
           {
               for (let f=1; f<=i; f++)
               document.write("* ");
           }
           document.write("<br>")
       }
       </script>
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