React Native：Fetch通过引用传递时无法检索令牌的值

Question

我正在尝试从下面的代码中获取响应。预期的响应是 400。当我在 fetch 调用中明确输入 ut 时，它可以工作。但是当我将 ut 作为变量传递时，出现以下错误

注意：retrieveUserToken() 从 AsyncStorage 获取令牌。

什么有效：当我在标题中输入这个时：它有效。

'Authorization': "Bearer eyJskfjvksndvjnsdknvlkandlkcnals"

Doesn't work: 

```'Authorization': "Bearer "+ ut

```onPress={async () => {
                       

                        const ut = await retrieveUserToken("token")
                        const data = {id: "myID", password:"mypass"}

                        await fetch("http://MY-URL", {
                          method: "POST",
                          
                          headers: {
                            "Content-Type": "application/json",
                            'Authorization':
                              "Bearer " + ut
                          },
                          body: JSON.stringify(data),
                        }).then(response => JSON.stringify( response))
                        .then(result => console.log(result))
                        .catch(error => console.log('error', error));
                      }}


ERROR:  {"type":"default","status":401,"ok":false,"headers":{"map":{"content-length":"0","server":"Kestrel","www-authenticate":"Bearer error=\"invalid_token\"","date":"Fri, 21 Aug 2020 03:23:00 GMT","content-type":"text/plain"}},"url":"http://63.35.183.253:9054/api/appointment","bodyUsed":false,"_bodyInit":{"_data":{"size":0,"offset":0,"blobId":"F5F055F9-8C4C-434D-AA39-11B58B0CE290","type":"text/plain","name":"appointment.txt","__collector":{}}},"_bodyBlob":{"_data":{"size":0,"offset":0,"blobId":"F5F055F9-8C4C-434D-AA39-11B58B0CE290","type":"text/plain","name":"appointment.txt","__collector":{}}}}

Answer 1

"www-authenticate":"Bearer error=\"invalid_token\"

这意味着ut === 'error=\"invalid_token\"'。即，您在检索令牌时遇到问题。当你回头看时：

const ut = await retrieveUserToken("token")

您确定要将字符串 "token" 作为arg 传递吗？