How to check if an asset exists

Question

I'm using pallet-assets to implement my own pallet. In one of the extrinsic calls I would like to check if an asset with the given ID exists. How to achieve this, given that Assets type is private and there's no getter provided?

Answer 1

I think you can use maybe_total_supply. This will return Some(supply) if the asset exists, and None otherwise https://github.com/paritytech/substrate/blob/0ba251c9388452c879bfcca425ada66f1f9bc802/frame/assets/src/functions.rs#L62

Answer 2

After you create the asset with for example pallet_assets::Pallet::<T>::force_create query pallet_assets::<T>::Balance with the asset id

let assetid: AssetId<T> = 1337u32.into();
let asset_balance: u128 = pallet_assets::Pallet::<T>::balance(assetid.into(), myaccount)
                .try_into()
                .unwrap_or(0u128);