简体   繁体   English

等待后承诺解决但数据未定义

[英]Promise resolves after awaited but data is undefined

JavaScript gurus, what am I missing here? JavaScript 大师,我在这里错过了什么?

Simple test scenario as follows:简单的测试场景如下:

   import * as request from "request-promise-native";

   export class Publisher {

        name : string = "IRocking Publisher";

        async publishAsync(): Promise<PublisherResponse> {

              var publisherResponse : PublisherResponse = PublisherResponse.EmptyResponse;

              try {

                    let response = await request.get("https://jsonplaceholder.typicode.com/todos/1");

                    console.debug("Promise has been resolved.  Result is:")
                    console.debug(response)

                    console.debug(response.userId)
                    publisherResponse = new PublisherResponse(file, this.name, true, "");
                  }
                  catch (error) {
                    publisherResponse = new PublisherResponse(file, this.name, false, error);
                 }

                return Promise.resolve<PublisherResponse>(publisherResponse); 
            }
    }

With accompanying Jest test as follows:随附 Jest 测试如下:

 test('Should publish a valid single document asynchronously', async () => {

      // Arrange

        let sut = new Publisher(); 
        let expectedResponse = new PublisherResponse(documentToPublish, sut.name, true, "");

        // Act
        let actualResponse = await sut.publishAsync(new PublicationContext(), documentToPublish);   

        // Assert
      expect(actualResponse).toEqual(expectedResponse);
      });

When I run the test, I see the data being returned from the service as当我运行测试时,我看到从服务返回的数据为

 {
        "userId": 1,
        "id": 1,
        "title": "delectus aut autem",
        "completed": false
      }

But if I attempt to access a property of the data such as "userId" I get undefined.但是,如果我尝试访问诸如“userId”之类的数据属性,则会出现未定义的情况。 What am I missing?我错过了什么?

Also, how do I get other status codes besides a 200 from this request?另外,除了这个请求中的 200 之外,我如何获得其他状态代码?

I needed to deserialize the JSON string returned from the service using我需要使用反序列化从服务返回的 JSON 字符串

  var todo = JSON.parse(response);

For some reason, I was assuming that the response to出于某种原因,我假设响应

let response = await request.get("https://jsonplaceholder.typicode.com/todos/1");

was an object but the underlying type is a string .是一个对象,但底层类型是一个string I found this out with the following code:我用以下代码发现了这一点:

   let propertyNames = Object.keys(response);
    console.debug(propertyNames);
    propertyNames.forEach((p, i) => {
              console.debug(response[p])
            })

声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.

 
粤ICP备18138465号  © 2020-2024 STACKOOM.COM