Increment a property value of an element in array object mongodb-node

Question

I am trying to increment a value of an element here's my array object

"options": [
    {
        "key": "banana",
        "votes": 0
    },
    {
        "key": "apple",
        "votes": 0
    },
    {
        "key": "mango",
        "votes": 0
    },
    {
        "key": "grapes",
        "votes": 0
    }
]

im trying to increment the votes value of the selected item while also matching the id of that data

  db().collection('polls').update( 
            { _id: id, "options.key": item },
            {$set:  { $inc: { "options.$.votes" : 1 } }})

But it didn't work... the db() here is a function that returns the db.. im not getting any errors.

here is the full data

{
    "_id": {
        "$oid": "5aae26203ab1cc0f15e43dc6"
    },
    "author": "me",
    "title": "fruits you love the most",
    "options": [
        {
            "key": "banana",
            "votes": 0
        },
        {
            "key": "apple",
            "votes": 0
        },
        {
            "key": "mango",
            "votes": 0
        },
        {
            "key": "grapes",
            "votes": 0
        }
    ]
}

Ankit Agarwal · Accepted Answer · 2018-03-19 09:07:16Z

2

Remove $set and try. It should work then. Also, the db should be used without paranthesis like db and not db():

db.collection('polls').update( 
   { _id: id, "options.key": item },
   { $inc: { "options.$.votes" : 1 } }
)

If you are running this query directly in your mongodb shell then you need to specify _id: ObjectId(id) in your query so your query will be:

var id = '5aaf66812b0e3813178a8a14'
db.collection('polls').update( 
   { _id: ObjectId(id), "options.key": item },
   { $inc: { "options.$.votes" : 1 } }
)

edited Mar 19, 2018 at 9:07

answered Mar 19, 2018 at 8:55

Ankit Agarwal

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2 Comments

Ankit Agarwal Over a year ago

Are you running this script from mongoose or directly on mongodb?

Ankit Agarwal Over a year ago

If its directly on mongodb then you should be using _id: ObjectId(id)

krishnashu · Accepted Answer · 2018-03-19 09:02:17Z

0

You are doing thing all correct but only one mistake is $inc should not be inside $set.

Following will fulfil your requirement.

    db.collection.update(
       {"options.key": "banana" },
       { $inc: { "options.$.votes" : 1 } }
    )

answered Mar 19, 2018 at 9:02

krishnashu

425 bronze badges

2 Comments

JEEZSUSCRIZE Over a year ago

this works but i also want to match the data id so it just updates that particular data..

krishnashu Over a year ago

then you can add data id field too in search filter. :)

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