🔎 Search Terms

Partial, @types/node, exactOptionalPropertyTypes, interface

🕗 Version & Regression Information

• This changed between versions v5.9.3 and 6.0.0-dev.20251001

⏯ Playground Link

https://www.typescriptlang.org/play/?exactOptionalPropertyTypes=true&ts=6.0.0-dev.20251008#code/HYQwtgpgzgDiDGEAEALALmmSDeBYAUEkhAB4wD2ATmkgJbBoSUBmCyAKvDAMrnwDWENAGFywYBHhoA8jDRQcBIkQrUAXEmABXMACMmAbiVIAvgWOlVNeoxZskAQQDmEBrLS0xC0o2AATBQAFEGpaEAAbAB5OHj5BETEJKXcoAD5FQmVBCBgHcNoANwgAfg1dcnJwiBBgJAAfJC1-CGZ6CD8jTLN8boJQSFh7NHCFPEzLKmsGJlZEJFFxSQ8xd09gUeMVSdLNHX1Kesbm1okO427e-BsZ+2dXGTk17xJfANQMGAA6O7dHrwAaJDDKCfBZJZbAVZeDJEMAgEjCBAodrcaBQJ47bR6JiHJp+FptM49AhAA

💻 Code

namespace http { export interface TcpSocketConnectOpts { port: number; } export interface AgentOptions extends Partial<TcpSocketConnectOpts> { keepAlive?: boolean | undefined; } } namespace tls { export interface ConnectionOptions { port?: number | undefined; } } interface AgentOptions extends http.AgentOptions, tls.ConnectionOptions { maxCachedSessions?: number | undefined; }

🙁 Actual behavior

This now fails to type check—I believe correctly, because Partial<{ port: number }> is { port?: number }, not { port?: number | undefined }. It’s surprising that this worked before.

🙂 Expected behavior

Actually, the new behavior is expected, so probably @types/node needs an update. I wanted to flag this in case/for when other folks hit it!

Additional information about the issue

• Happens on latest @types/node.
• Discovered via True Myth’s nightly TS@next CI job as well as dependabot upgrades that test. The semver-ts.org guidance to test against upcoming versions is: good!