Error Pattern Matching in Swift
Swift errors can be pattern matched by their value. It’s useful when switching over an error. Any Error-conforming type is applicable, including the custom ones:
import Foundation
import CFNetwork
let error: Error = URLError(.badURL)
enum MyError: Error {
case myError
}
switch error {
case URLError.badURL:
print("Bad URL error found")
case CFNetworkErrors.cfErrorHTTPBadCredentials:
break
case DecodingError.dataCorrupted:
break
case MyError.myError:
break
default:
break
}
It will print:
Bad URL error found
Note how we are using different error types in a single switch statement. NSErrors can be used as well: they will be bridged automatically to Swift Errors.
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