无法转换Promise(_，_)->类型的返回表达式返回类型Promise< DataResponse，AnyObject>>的DataRequest. [英] Cannot convert return expression of type Promise (_,_) -> DataRequest to return type Promise<DataResponse,AnyObject>>

问题描述

无法将Promise(，)类型的返回表达式转换为DataRequest以返回Promise>类型的

我的功能是

func postJson(_ url: String, parameters: [String: String]) -> Promise<DataResponse<AnyObject>> {

        var request = URLRequest(url: URL(string: url)!)
        request.httpMethod = "POST"
        request.setValue("application/json", forHTTPHeaderField: "Content-Type")

        request.httpBody = try! JSONSerialization.data(withJSONObject: parameters)

        return Promise { fulfill, reject in

        manager.request(request)
            .responseJSON { response in
                fulfill(response)
        }

然后在Promise返回行中收到此错误.如何转换?

我尝试将返回签名更改为Promise<DataRequest, Error，并在该行上看到编译错误，因为Promise过于专门化了2个参数而不是1个参数.

解决方案

fulfill存在问题，因为它需要参数DataResponse<AnyObject>，但是您正在传递DataResponse<Any>.

将postJson方法的返回类型更改为Promise<DataResponse<Any>>应该可以解决您的问题.

更改此行

func postJson(_ url: String, parameters: [String: String]) -> Promise<DataResponse<AnyObject>> {

到

func postJson(_ url: String, parameters: [String: String]) -> Promise<DataResponse<Any>> {

Cannot convert return expression of type Promise (,) -> DataRequest to return type Promise>

my function is

func postJson(_ url: String, parameters: [String: String]) -> Promise<DataResponse<AnyObject>> {

        var request = URLRequest(url: URL(string: url)!)
        request.httpMethod = "POST"
        request.setValue("application/json", forHTTPHeaderField: "Content-Type")

        request.httpBody = try! JSONSerialization.data(withJSONObject: parameters)

        return Promise { fulfill, reject in

        manager.request(request)
            .responseJSON { response in
                fulfill(response)
        }

And I get this error on the return Promise line. How do I convert ?

I tried changing my return signature to Promise<DataRequest, Error and get a compile error on that line that Promise is too specialized with 2 parameters instead of 1.

解决方案

Problem is with fulfill because it's expecting parameter DataResponse<AnyObject> but you are passing DataResponse<Any>.

Changing return type of your postJson method to Promise<DataResponse<Any>> should solve your problem.

Change this line

func postJson(_ url: String, parameters: [String: String]) -> Promise<DataResponse<AnyObject>> {

to

func postJson(_ url: String, parameters: [String: String]) -> Promise<DataResponse<Any>> {

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