Push Data into Array in Loopback Model

Question

I am new to Loopback and working on a project where I have the following Model and Document.

{
    "_id" : ObjectId("5c9b44cc618c1bbe8780e38b"),
    "userId" : ObjectId("5bae3ea215e11e0018b914c1"),
    "providers" : [ 
        "1629132790", 
        "1467401216", 
        "1356405641", 
        "1952465288", 
        "1447314513", 
        "1003803495"
    ],
    "countByType" : {
        "doctors" : 2,
        "laboratories" : 3,
        "hospitals" : 1,
        "imagingCenters" : 0
    }
}

I am basically trying to add a new item to an array in base class Model. When a new user is created, an empty array is added for 'providers'. There is no model for providers. It is just an array which can hold a list of providers.

How do I add a new providerId to the list of providers if providerId is not there(Add a string to the list)?

This is my Provider Model

{
  "name": "UserProviders",
  "base": "Model",
  "idInjection": true,
  "options": {
    "validateUpsert": true
  },
  "properties": {
    "userId": {
      "type": "objectId",
      "required": true,
      "index": {
        "unique": true
      }
    },
    "providers": {
      "type": [
        "any"
      ],
      "default": []
    },
    "countByType": {
      "type": "object",
      "default": {
        "doctors": 0,
        "labs": 0,
        "hospitals": 0,
        "imagingCenters": 0
      }
    }
  },
  "validations": [],
  "relations": {},
  "acls": [],
  "methods": {}
}

Any help would be really appreciated.

Answer 1

I would do two things: first, I would add a custom model method for adding a new provider (that accepts both one string or array of strings), for example:

const provider = async Provider.findOne({id: someId});
provider.addProviders([value1, value2]);
await provider.save();

Then, to make sure that it won't save rubbish values, I would add a custom validator that checks for duplicates in the array before you save the instance and throws an error or removes duplicates. You can read here how to add a custom validation function to your model.