still unsure how to get balance from Digital Asset

[dellwatson]

I only get how to get the address instead of balance of my total NFT

https://github.com/aptos-labs/aptos-core/blob/93ed9aefff550250ecc620651cd3eb4cf37ecc40/aptos-move/framework/aptos-token-objects/sources/token.move#L280C1-L283C6

    /// Generates the token's address based upon the creator's address, the collection's name and the token's name.
    public fun create_token_address(creator: &address, collection: &String, name: &String): address {
        object::create_object_address(creator, create_token_seed(collection, name))
    }
    ```
    
    I dont find function that return the number of balance here.
    why not make it same like from EIP-712 ? with token index, ownerOf etc

[0xaptosj]

The only way to get your NFT balance in a collection is to query indexer, because Aptos's digital asset standard (and fungible asset) is based on object, i.e. it's more like UTXO model where we try to store data under each user instead of like account model where we store all users' data in one big table.

  import { Aptos, AptosConfig, Network } from "@aptos-labs/ts-sdk";
  const config = new AptosConfig({
    network: Network.TESTNET,
  });
  export const aptos = new Aptos(config);

  const result = await aptos.getAccountOwnedTokensFromCollectionAddress({
    accountAddress: ownerAddr,
    collectionAddress: COLLECTION_ID,
  });

  console.log("my nfts in the collection", result);

[dellwatson]

so it's unable to get balance on-chain? since i need the smart contract to detect balance of the collections

[0xaptosj]

If you want the total supply of NFT in a collection, you can do this

use aptos_token_objects::collection::Collection;
use aptos_framework::object::address_to_object;

let collection_object = address_to_object<Collection>(collection_address);
collection::count(collection_object)

If you want to count how many NFT an address has, unfortunately you can not get that on chain, you have to use indexer