JQuery ajax for (async : false)

for(let i=0; i<row.length; i++){
  (function(i){
    $.ajax({
      url: your url,
      type: 'POST',
      dataType: 'json',
      contentType: 'application/json; charset=utf-8',
      async:false,
      data: JSON.stringify({
        providerSeq : row[i].providerSeq,
        promotionType : 0
      }),
      success: function (res) {
      	result = true;
      },
      error: function (jqXHR) {
        alert(jqXHR.responseText);
        result = false;
      },
    });
  })(i);
}