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July 8, 2016 09:51
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A `safeValue` method for Optional type. It returns an empty value if the wrapped type of the Optional type has one, for example String and Array.
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/// A type that supports an "empty value" | |
protocol EmptyValuable { | |
/// Returns the empty value of `Self` | |
static var emptyValue: Self { get } | |
} | |
extension String: EmptyValuable { | |
static var emptyValue: String { | |
return "" | |
} | |
} | |
extension Array: EmptyValuable { | |
static var emptyValue: [Element] { | |
return [] | |
} | |
} | |
extension Optional where Wrapped: EmptyValuable { | |
/// If `self` is non-`nil`, returns the unwrapped value. Otherwise, returns an empty value of the `Wrapped` type | |
var safeValue: Wrapped { | |
return self != nil ? self! : Wrapped.emptyValue | |
} | |
} |
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