I'm wanting to update fields in nested array in mongodb

Question

here's my document:

{
"_id": {
 "$oid": "5eb5f0a9d985888edb0523b0"
},
"subs": [{
 "name": "list1",
 "count": "0"
}, {
 "name": "list2",
 "count": "0"
}, {
 "name": "list3",
 "count": "0"
}, {
 "name": "list4",
 "count": "0"
}]
}

I'm using mongojs currently. I'd like to be able to for instance, find "list2" and increment the count associated with it. I have tried all day and can't seem to figure it out.

any help or direction would be greatly appreciated!

• fedeteka: I think is using array filters: docs.mongodb.com/manual/reference/command/update/… - stackoverflow.com/questions/51605347/…
• Aravinda Meewalaarachchi: is you try to update the values only using mongojs provided functions or just need to update those values by using javascript functions?
• Mickael B.: Can you show us what you've tried ? And as @AravindaMeewalaarachchi pointed do you want a raw mongodb query or you want to use the library ?

Answer 1

I hope this will help you. I have use programmatic approach to solve your problem.

let payload = {
"_id": {
 "$oid": "5eb5f0a9d985888edb0523b0"
},
"subs": [{
 "name": "list1",
 "count": "0"
}, {
 "name": "list2",
 "count": "0"
}, {
 "name": "list3",
 "count": "0"
}, {
 "name": "list4",
 "count": "0"
}]
}
let fields = ["list2","list4"];
fields.forEach((element)=>{
 for(let i=0; i<payload.subs.length; i++){
 if(element===payload.subs[i]["name"]){
 let value = parseInt(payload.subs[i]["count"]);
 payload.subs[i]["count"] = (++value).toString();
 }
 }
})
console.log(payload.subs)

Answer 2

{
"_id": {
 "$oid": "5eb5f0a9d985888edb0523b0"
},
"subs": [{
 "name": "list1",
 "count": 0
}, {
 "name": "list2",
 "count": 0
}, {
 "name": "list3",
 "count": 0
}, {
 "name": "list4",
 "count": 0
}]
}

The answer is not based on mongojs but the syntax below should assist you.

db.collection.updateOne(({"subs.name":"list2"},{$inc:{"subs.$.count":1}})

Make sure that your count is int32 not a string. "Count": 0 not "Count":"0"