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fold

inline fun <A, B> A?.fold(ifNull: () -> B, ifSome: (A) -> B): B

Fold higher order function reduces the left or right side into a return value

Example usage:

null.fold({ 1 }, ::id)

1.fold(
 ifNull = { 1 },
 ifSome = ::id
)

Parameters

ifNull - the lambda will be applied in case of a left side value.

ifSome - the lambda will be applied with the right side value.

Receiver the value it will be folded over

Return result of $ifNull if the $receiver is null otherwise the result of $ifSome