How to convert substrate Specific Types(Option<BalanceOf<T>> ) to Rust Primitive types (U64)?

Question

I don't know how can I convert Option<BalanceOf> (subtrate specific type)to u64 (rust primitive types)?

I followed this article( How do you convert between Substrate specific types and Rust primitive types? ), it helped me while converting u64 to Option<BalanceOf using the below function.

    pub fn u64_to_balance_option(input: u8) -> Option<BalanceOf<T>> {
            input.try_into().ok()
        }

But I also need to convert some Option<BalanceOf> types inside u64 to perform some mathematical operation and then again convert u64 to Option<BalanceOf> to put back inside my storage items.

Thank you

Answer 1

You'll see that Currency::Balance is bound to AtLeast32BitUnsigned which by being bound to BaseArithmetic is bound to implement TryInto<u64>. Therefore the most obvious code is something like:

pub fn balance_to_u64_option(input: impl TryInto<u64>) -> Option<u64> {
    input.try_into().ok()
}

However, balances cannot necessarily be expressed as a u64, so this really isn't such a great plan for production code as it will restrict your pallet to being used only when someone has a small enough balance.

In general, you should aim to do all arithmetic in the native Polkadot types. Currency::Balance is required to implement all the typical arithmetic operations for this reason.