Question

在我的程序中，我有一个方法可以返回MyClass或Observable.of(null)的可观察对象。代码如下：

doSomething(someParams) {    
      return this.backEnd.getStuff(someParams)
                    .switchMap(data => {
                        if (!data ) {
                            return Observable.of(null);
                        } else {
                            this.doSomethingElse(data);
                        }
                    });
}

其中doSomethingElse（）返回Observable<MyClass>。

如果我按上述方法编写方法，我会松开智能感知，因为我的IDE（VSCode）告诉我方法doSomething（）返回一个Observable。

在这种情况下，有没有办法保持智能感知？我想要的是IDE建议我doSomething（）方法返回一个Observable<MyClass>并自然地进行逻辑检查，实际上有一个MyClass或null的实例。结果已订阅。

Answer 1

您可以在spXML 'Gender','''/CreateAndSendMessageRequest/CompositionRequest/PolicyDetails /MainPolicyHolder/PolicyHolderDetails''' ALTER PROCEDURE spXML @lasttag VARCHAR(50), @root VARCHAR(MAX) AS BEGIN Declare @xml xml Set @xml = '<?xml version="1.0" encoding="utf-8"?> <CreateAndSendMessageRequest> <CompositionRequest> <Metadata> <PolicyReference>250028766622DN</PolicyReference> <AccountReference>Test1234</AccountReference> <QuoteReference>Test3214</QuoteReference> <OutboundTransactionID>string</OutboundTransactionID> <InboundActivityID>string</InboundActivityID> <DocumentName>DocumentA127</DocumentName> <DocumentID /> <CommunicationID>C004</CommunicationID> <CorrelationID>PC: 20c14f9b-2a1b-45dc-b680-52ffceb86d05</CorrelationID> <ContentType>string</ContentType> <isSensitive>true</isSensitive> <isReadOnly>true</isReadOnly> <isDocumentInbound>true</isDocumentInbound> <ChannelIdentifier>POST</ChannelIdentifier> <BrandType>string</BrandType> <SchemeNameCode>string</SchemeNameCode> <isNotificationRequiredIndicator>false</isNotificationRequiredIndicator> <DocumentPriorityIndicator>Standard</DocumentPriorityIndicator> <SpecialInstructions> <Code>string</Code> <Description>string</Description> </SpecialInstructions> <SupressIndicator>false</SupressIndicator> <OutsortIndicator>string</OutsortIndicator> <DocumentIncludes> <DocumentId DocumentTitle="string">string</DocumentId> </DocumentIncludes> <CreatedBy>string</CreatedBy> <UpdatedBy>string</UpdatedBy> <FulfilledDateTime>2017-05-15T07:41:13</FulfilledDateTime> <UploadedDateTime>2013-12-21T17:02:42+05:30</UploadedDateTime> <RequestDateTime>2016-01-01T19:07:42</RequestDateTime> <UpdateDateTime>2012-01-07T19:42:56</UpdateDateTime> </Metadata> <PolicyDetails> <PolicyReference>string</PolicyReference> <QuoteReference>string</QuoteReference> <PolicyVersionStartDate>2009-11-03</PolicyVersionStartDate> <MainPolicyHolder> <PolicyHolderDetails> <Title>string</Title> <Initials>string</Initials> <Honours>string</Honours> <Firstname>string</Firstname> <Surname>string</Surname> <FullName>string</FullName> <Gender>F</Gender> <DateOfBirth>2018-04-13</DateOfBirth> </PolicyHolderDetails> </PolicyDetails> </CompositionRequest> <VersionInfo majorVersion="1" minorVersion="19" /> </CreateAndSendMessageRequest>' Declare @tag varchar(max) set @tag = 'Select X.T.value(''('+@lasttag+')[1]'',''varchar(50)'') as Result From @xml.nodes('+@root+') as X(T)' print @tag Execute(@tag) End为union type的Observable<MyClass | null>处输入您的退货类型：

MyClass | null

打字稿：将类型定义添加到Observable.of（null）

1 个答案: