I have a javascript file ( .js ) that works on MongoDB. I run the .js file as mongo localhost:27017/dbname myjsfile.js .
How can I send command line arguments while running this JavaScript file ? I want to send database name and collection name as command line argument.
Well, you are already setting the database in use as you connect via:
mongo localhost:27017/dbname
So it is now on database "dbname". That is carried through to the db variable. Which is just a placeholder for the "current" database object.
That means that anything in your "script":
var results = db.collection.find().toArray();
For example is using the database you selected and the collection you named.
Need more? This is valid to:
db["mycollection"].find();
It's just JavaScript to the shell.
if you want a collection to be set as a variable then do something like this:
mongo localhost/mydb --eval "var users = db.users" myfile.js
Or otherwise just do that in you JavaScript file. You can test that by:
mongo localhost/mydb --eval "var users = db.users" --shell
And in the shell you now have a variable users that is "aliased" to the users collection.
load() JavaScript. Plus, the question asked "from the command line" And your answer says, "no you cannot". Hence the comment.cli argument no. But you can read a json file and parse it in your script.
// config.json - {"dbname":"dbname","collection":"mycollection"}
var args = JSON.parse(cat("config.json"));
load() for additional files. But of course you can use --eval on the command line as I have demonstrated. Have a look and a try yourself.