Error on get PaymentMethodList when working with currencies without decimal places (PaymentMethodClient)

[Flo301]

Hi there, want to report another finding.

How to reproduce?

Take a currency from the mollie list (https://docs.mollie.com/payments/multicurrency) which has no decimal places like Japanese yen (JPY) and create a new Amount("JPY", 249M) object. Now take the Amout as parameter for the GetPaymentMethodList method. It will return a error => Bad Request - The amount contains an invalid value

Example:

var methodsResponse = await _paymentMethodClient.GetPaymentMethodListAsync(amount: new Amount("JPY", 249M));

Conclusion:

Using the constructor of Amount with a decimal value will always set a string with two decimal places to Amount.Value 249M => "249.00". So this solution works not for currencies without decimals places.

Workaround:

ILS and JPY are the only currencies without decimal places, so ...

var _amount = new Amount(currency, value);
if (_amount.Currency == "ILS" || _amount.Currency == "JPY")
{
   _amount.Value = value.ToString("0");
}

For sure there is a better way to handle this. Let me know what you are thinking

[Viincenttt]

Hi @Flo301 ,

You are right, this looks like a bug. At the moment, the Amount constructor always sets the amount value to 2 decimals, regardless of currency. I think the best way to solve this would be to add a extra optional constructor argument with a default value of 2, that holds the number of decimal places. For example:

public Amount(string currency, decimal value, int numberOfDecimalPlaces = 2) {
            this.Currency = currency;
            // Add code here to use numberOfDecimalPlaces 
            this.Value = value.ToString("0.00", CultureInfo.InvariantCulture);
        }

Since this library is a API wrapper, I don't want to maintain a list of currencies and the number of decimal places they have. I found this list on Wikipedia: https://en.wikipedia.org/wiki/ISO_4217 and there are quite some exceptions.

[Viincenttt]

This is now live in 2.2.0.4