mongo_export.js

// mongo export to csv
// Usage "$ mongo localhost:27017/my_db script.js > test.csv "
cursor = db.collection.find();
var fields = [
"field1",
"field2",
"field3",
"field4",
"created_field"
];
print(fields.join(","));
while ( cursor.hasNext() ) {
  row= cursor.next();
  row.created_field = row.list ? row.list.reduce(function(prev, cur){
    return prev + (cur.doc_code === "ABCD" ? 1: 0);
  },0): 0;


  var csv_row = "";
  fields.forEach(function(col, index){
    if(index < (fields.length-1)){
      csv_row += "\"" + (row[col] ? row[col] : "") + "\t\",";
    }else{
      csv_row += "\"" + (row[col] ? row[col] : "") + "\t\"";
    }
  });
   print(csv_row);
}