let len = 5;

for (let i = len; i >= 1; i--) {
  let line = '';
  for (let j = 0; j < i; j++) {
    line += '* ';
  }
  
  // boşluk ekle
  for(let j = (len - i) * 2; j >= 1; j--){
    line += "  ";
  }
  
  for (let j = 0; j < i; j++){
     line += "* ";
  }
  
  console.log(line);
}


for (let i = 1; i <= len; i++) {
  let line = '';
  for (let j = 1; j <= i; j++) {
  line += '* ';
  }
  // boşluk ekle
  for(let j = (len - i) * 2; j >= 1; j--){
    line += "  ";
  }
  
  for (let j = 1; j <= i; j++){
     line += "* ";
  }
  
  console.log(line);
}