jsのreplaceはすべて動態的な文字列を交替します.


jsは繰り返しの言葉を動的に置き換えます.
  let title = ”    “;
  let doubleTitle = title;
  arrPara[i] = arrPara[i].replace(new RegExp(doubleTitle,'gm'),title);//  1
  arrPara[i] = arrPara[i].replace(doubleTitle,"");//  2