whenOrNull<TResult extends Object?> method

  1. @optionalTypeArgs
TResult? whenOrNull<TResult extends Object?>(
  1. TResult? $default(
    1. ExpressApplePayButtonType? applePay,
    2. ExpressGooglePayButtonType? googlePay,
    3. ExpressPaypalButtonType? paypal
    )?
)

A variant of when that fallback to returning null

It is equivalent to doing:

switch (sealedClass) {
  case Subclass(:final field):
    return ...;
  case _:
    return null;
}

Implementation

@optionalTypeArgs TResult? whenOrNull<TResult extends Object?>(TResult? Function( ExpressApplePayButtonType? applePay,  ExpressGooglePayButtonType? googlePay,  ExpressPaypalButtonType? paypal)?  $default,) {final _that = this;
switch (_that) {
case _ExpressCheckoutButtonType() when $default != null:
return $default(_that.applePay,_that.googlePay,_that.paypal);case _:
  return null;

}
}