$inc is not working in embedded object loopback 3

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I am using loopback 3. In which I have model Item and that have embedded object `availableQtyBranchWise`. I was trying to update the `availableQtyBranchWise` using `$inc` but with this operator i got validation error.

Item.json
```
{
"name": "Item",
"base": "PersistedModel",
"idInjection": true,
"options": {
"validateUpsert": true,
"strictObjectIDCoercion": true
},
"properties": {
"name": {
"type": "string"
},
"barcode": {
"type": "number"
}
},
"relations": {
"branchWiseAvailableQtyE": {
"type": "embedsMany",
"model": "BranchWiseAvailableQtyE",
"property": "branchWiseAvailableQty",
"options": {
"validate": false,
"forceId": true
},
"description": "branchWiseAvailableQtyE is used to store branch wise available quantity"
}
}
}
```

Branch Wise Available Qty Embedded Schema

```
{
"name": "BranchWiseAvailableQtyE",
"base": "Model",
"idInjection": true,
"options": {
"validateUpsert": true
},
"properties": {
"refBranchName": {
"type": "string",
"required": true
},
"refBranchId": {
"type": "string",
"required": true
},
"refBranchCode": {
"type": "string",
"required": true
},
"availableQty": {
"type": "number",
"required": true,
"default": 0
}
},
"validations": [],
"relations": {},
"acls": [],
"methods": {}
}

```

In DB Data should look like

```
{
"_id": {
"$oid": "66e90d94c2d97907244dfae0"
},
"name": "01 PlK 1 1000 SERIES",
"branchWiseAvailableQty": [
{
"refBranchName": "Delhi",
"refBranchId": {
"$oid": "6204c8d8e1300e2ea8420483"
},
"refBranchCode": "DL",
"availableQty": 20,
"id": {
"$oid": "f3ef503f555877c69cc8ed6a"
}
},
{
"refBranchName": "Mumbai",
"refBranchId": {
"$oid": "6204c8d8e1340e2ea8420483"
},
"refBranchCode": "MU",
"availableQty": 40,
"id": {
"$oid": "f3ef503f555987c69cc8ed6a"
}
}
],
"barcode": 1856
}
```

I was trying to increment, decrement `availableQty` when object exists and add object when does not exist.

This is my code where I update the `availableQty`

```
item.branchWiseAvailableQtyE.set(ObjectId(f3ef503f555987c69cc8ed6a),{ availableQty: {$inc: 10}}, null, function(err, result) {
if (err) {
return reject(err);
}
return resolve(result);
});
```

This give me validation error because I am using
```
{ availableQty: {$inc: 10}}
```

But If I use this syntax it works

```
{ availableQty: 10}
```

Please help me. Thanks, in advance

Start with the Item.json embedsMany relation and the BranchWiseAvailableQtyE embedded schema, then reproduce the validation error at the branchWiseAvailableQtyE.set call using the shown $inc value. Trace how embedded-object updates are validated and determine whether incrementing availableQty and adding a missing object are supported; done means the supported behavior or required change is clearly established.

Written by the indexing model from the issue text.