TS compilation error when exactOptionalPropertyTypes set true

[victorsmirnov]

General Issue

TypeScript compilation fails when exactOptionalPropertyTypes is set to true

The Question

Compilation fails when exactOptionalPropertyTypes is set to true.

Several other modules also have the same error.

> tsc

node_modules/aws-cdk-lib/aws-apigateway/lib/restapi.d.ts:226:31 - error TS2420: Class 'RestApiBase' incorrectly implements interface 'IRestApi'.
  Types of property 'latestDeployment' are incompatible.
    Type 'Deployment | undefined' is not assignable to type 'Deployment'.
      Type 'undefined' is not assignable to type 'Deployment'.

226 export declare abstract class RestApiBase extends Resource implements IRestApi {
                                  ~~~~~~~~~~~

CDK CLI Version

2.13.0

Framework Version

2.13.0

Node.js Version

16.12.0

OS

macOS Big Sur

Language

Typescript

Language Version

TypeScript (4.5.5)

Other information

Most likely, replacing readonly latestDeployment?: Deployment; with readonly latestDeployment: Deployment | undefined; should fix the issue. I can try this as my first issue in the project. Please let me know if I should make a pull request.

[longtv2222]

Can confirm that I'm facing the same issue here, please refer https://devblogs.microsoft.com/typescript/announcing-typescript-4-4/#exact-optional-property-types to know why this is an issue.

[mpellegrini]

Hello, wondering if there is any updates on this issue. My current work around is to explicity cast the concrete class as the specific interface - vpc as IVpc or table as ITable. But for anyone using a later version of Typescript with a default config will be hitting this issue.

[kenberkeley]

Same here 😮‍💨

Type 'Cluster' is not assignable to type 'ICluster' with 'exactOptionalPropertyTypes: true'. Consider adding 'undefined' to the types of the target's properties.
  Types of property 'defaultCloudMapNamespace' are incompatible.
    Type 'INamespace | undefined' is not assignable to type 'INamespace'.
      Type 'undefined' is not assignable to type 'INamespace'.ts(2375)

---

Temp fix is using as

[TheRealAmazonKendra]

This is a TypeScript 4.4 feature and the CDK is on 3.9. At this time we cannot upgrade our TypeScript version so there's no action item we can take here. See aws/aws-cdk-rfcs#373 for more information on this.

Given the lack of actions to be taken at this time, I'm going to convert this to a discussion so that others can find this context.

[lo1tuma]

Is there any update on this issue? Seems like the mentioned RFC has been accepted and merged. So what would be the next steps in order to update the types in CDK so they don’t conflict with enabled exactOptionalPropertyTypes?