When I run below stored JavaScript function I get errors:
> db.system.js.save({_id:"last_n_users", value: function(n){return db.users.find().sort({created_at:-1}).limit(n)}})
> db.eval("last_n_users(10)")
Here is the errors:
{ "value" : "DBQuery: store.users -> undefined" }
Why? Please help me?
The find() function returns a cursor, which can't be returned from JavaScript. The suggested workaround is to use toArray() to get an array return value.
Example ... before :
> use admin
switched to db admin
> db.system.js.save( { _id : "foo", value: function(n){return db.system.indexes.find().limit(n)} } )
> db.eval( "foo(3)" )
{ "value" : "DBQuery: admin.system.indexes -> undefined" }
just as you describe.
And after:
> db.system.js.save( { _id : "foo", value: function(n){return db.system.indexes.find().limit(n).toArray()} } )
> db.eval( "foo(3)" )
[
{
"name" : "_id_",
"ns" : "admin.system.users",
"key" : {
"_id" : 1
}
},
{
"name" : "user_1",
"ns" : "admin.system.users",
"key" : {
"user" : 1
},
"unique" : false
},
{
"name" : "_id_",
"ns" : "admin.whee",
"key" : {
"_id" : 1
},
"v" : 0
}
]
