这段代码
let promise: Promise<Supplier> = self.supplierController
.update(supplier: supplier)
let block: ((Error) throws -> Supplier) = { (error: Error) throws -> Supplier in
let supplier: Supplier = supplier
guard (error as NSError).code == 405 else {
throw error
}
return supplier
}
let newPromise =
promise
.recover(block)
.done { (_: Supplier) in
changeCompanyIdAndAppendMessage()
}
给出编译时错误
invalid conversion from throwing function of type '(Error) throws -> Supplier' to non-throwing function type '(Error) -> Guarantee'
为什么要尝试转换?在我看来,它必须使用这个函数:
public func recover(on: DispatchQueue? = default, policy: PromiseKit.CatchPolicy = default, _ body: @escaping (Error) throws -> U) -> PromiseKit.Promise where U : Thenable, Self.T == U.T
来自 PromiseKit
我添加了显式类型并将 promise 分成 block ,以免遗漏任何内容
最佳答案
您应该返回 Promise 以正确链接,如下所示:
self.supplierController
.update(supplier: supplier)
.recover { error -> Promise<Supplier> in
let supplier: Supplier = supplier
guard (error as NSError).code == 405 else {
throw error
}
return .value(supplier)
}
.done { (_: Supplier) in
changeCompanyIdAndAppendMessage()
}
来源:https://github.com/mxcl/PromiseKit/blob/master/Documentation/CommonPatterns.md
关于swift - 恢复 block 的无效转换,PromiseKit,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/51023774/