Increment key based on another field

[iamchathu]

Let's say we have Incremented Value(ref) in the document which need to be incremented based on another field(shopId)

{
   "ref": 12,
   "shopId":1
},
{
   "ref": 13,
   "shopId":1
},
{
   "ref": 1,
   "shopId":2
},
{
   "ref": 2,
   "shopId":2
},
{
   "ref": 14,
   "shopId":1
}

What kind of approach can we have? ( the two properties are compound index)

[hasezoey]

with this plugin currently not possible
(increment value based on other value)

[tiennguyen1203]

Any update on this?

[hasezoey]

like it was said earlier in the comments, it is currently not possible.

if you want it yourself, either implement it and send a PR or better explain what is necessary / wanted.

to summarize (on my understanding), you would need a external (like AutoIncrementID) tracker for the base number, but increment it by another field before applying, tracker + field = newid; or am i misunderstanding something?

[MxBlu]

I just happen to come across this old issue, which I happened to have solved myself a few years back (if I'm interpreting the problem correctly).

If the issue is that you want a separate counter in the same collection based on the value of another field, check out the change I added to a (very) old version of auto-increment, based on the original mongoose-auto-increment: v0.9.0...MxBlu:auto-increment:master
Just look at the changes inside the src folder.

Taking a cursory glance at the latest version of this repo, my changes should still work. I'm not interested in maintaining my old repo but anyone is free to take these changes for themslves.

[hasezoey]

@MxBlu if i understand your code correctly, that change will allow you to have a different counter document depending on the value of another field, ie:

// a document for shop "a"
{
  for_shop: "a",
}
// would use tracker
{
  field: "_id",
  modelName: "SomeModel",
  count: 10,
  reference_values: {
    for_shop: "a"
  }
}

// where as a document for shop "b"
{
  for_shop: "b"
}
// would use a different tracker document
{
  field: "_id",
  modelName: "SomeModel",
  count: 5,
  reference_values: {
    for_shop: "b"
  }
}
// for the same model

if it this is wanted, it could easily be added (thanks to your code), though i am still not fully sure if this is what OP wanted out of this.

[MxBlu]

Exactly yea, and agreed.

I'm just leaving this here for anyone that stumbles upon it in the future, since the issue description happened to be how I described my problem too.