Importing json from file into mongodb using mongoimport

The mongoimport tool has an option:

--jsonArray treat input source as a JSON array

Or it is possible to import from file containing same data format as the result of db.collection.find() command. Here is example from university.mongodb.com courseware some content from grades.json:

{ "_id" : { "$oid" : "50906d7fa3c412bb040eb577" }, "student_id" : 0, "type" : "exam", "score" : 54.6535436362647 }
{ "_id" : { "$oid" : "50906d7fa3c412bb040eb578" }, "student_id" : 0, "type" : "quiz", "score" : 31.95004496742112 }
{ "_id" : { "$oid" : "50906d7fa3c412bb040eb579" }, "student_id" : 0,       "type" : "homework", "score" : 14.8504576811645 }

As you can see, no array used and no comma delimiters between documents either.

I discover, recently, that this complies with the JSON Lines text format.

Like one used in apache.spark.sql.DataFrameReader.json() method.

Side note:
$ python -m json.tool --sort-keys --json-lines < data.jsonl
also can handle this format
see demo and details here