PromiseKit の使い方。
enum SampleError: Error {
case error
}
_ = Promise { fulfill, reject in
if true {
fulfill()
} else {
reject(SampleError.error)
}
}
// fulfill promise
_ = Promise(value: ())
// reject promise
_ = Promise(error: SampleError.error)
enum SampleError: Error {
case error, unexpected(String)
}
firstly {
Promise(value: "Hello")
}.then { value in
Promise(value: value + ", World")
}.then { value in
print(value) // => Hello, World
return Promise(error: SampleError.unexpected("Error Happened"))
}.always {
print("Always called.")
}.catch { error in
switch error {
case SampleError.error:
print("Some error")
case SampleError.unexpected:
print(error) // => Error Happened
default:
break
}
}