Missing dependency for @types/launchdarkly-eventsource

[tlevesque-ueat]

Describe the bug

Got this error after upgrading from 6.1.3 to 6.4.3:

tsc -b tsconfig.build.json
Error: node_modules/unleash-client/lib/repository/index.d.ts(9,29): error TS7016: Could not find a declaration file for module 'launchdarkly-eventsource'. '/home/runner/work/(redacted)/node_modules/launchdarkly-eventsource/lib/eventsource.js' implicitly has an 'any' type.
Try npm i --save-dev @types/launchdarkly-eventsource if it exists or add a new declaration (.d.ts) file containing declare module 'launchdarkly-eventsource';

Shouldn't @types/launchdarkly-eventsource be listed as a dependency?

Steps to reproduce the bug

In a project using Typescript, upgrade from 6.1.3 to 6.4.3 (not sure when the dependency on launchdarkly-eventsource was introduced, maybe 6.3.0)
Try to compile.

Expected behavior

Should compile without issue

Logs, error output, etc.

Error: node_modules/unleash-client/lib/repository/index.d.ts(9,29): error TS7016: Could not find a declaration file for module 'launchdarkly-eventsource'. '/home/runner/work/(redacted)/node_modules/launchdarkly-eventsource/lib/eventsource.js' implicitly has an 'any' type.
  Try `npm i --save-dev @types/launchdarkly-eventsource` if it exists or add a new declaration (.d.ts) file containing `declare module 'launchdarkly-eventsource';`

Screenshots

No response

Additional context

No response

Unleash version

6.4.3

Subscription type

Open source

Hosting type

Hosted by Unleash

SDK information (language and version)

No response

[tlevesque-ueat]

Oh wait. There isn't a @types/launchdarkly-eventsource package 🤦‍♂

[tlevesque-ueat]

Actually, I think something could still be done to improve the experience.
Right now I need to manually declare the module in a .d.ts file, like this:

declare module 'launchdarkly-eventsource';

This could either be done directly in the unleash-client package, or the import from launchdarkly-eventsource could have a //@ts-ignore to ignore the missing typings.

[kwasniew]

Hi @tlevesque-ueat. The dependency was added for Unleash to test experimental SSE support. Can you let us know if you're getting this error when using unleash-client-node package as a dependency in your project or building a custom package from the sources yourself?

[Tymek]

@tlevesque-ueat did you try to add node_modules to exclude in your tsconfig.json?

[tlevesque-ueat]

Hi @tlevesque-ueat. The dependency was added for Unleash to test experimental SSE support. Can you let us know if you're getting this error when using unleash-client-node package as a dependency in your project or building a custom package from the sources yourself?

Hi, I'm using it as a dependency in my project. I'm not using SSE support.

@tlevesque-ueat did you try to add node_modules to exclude in your tsconfig.json?

It's already excluded.

[kwasniew]

Can you provide us with a minimal reproduction case so that we can debug it? Ideally a mini setup with package.json and tsconfig that you use?

[kwasniew]

BTW we already have // @ts-expect-error on the untyped eventsource library usage itself.

[tlevesque-ueat]

OK, here's the simplest repro I could make:
https://github.com/tlevesque-ueat/test-unleash-node-client

Build it with npm run compile to see the error.

Basically, I think you just need to import something from unleash-client with noImplicitAny set to true in the TS compilation options.

BTW we already have // @ts-expect-error on the untyped eventsource library usage itself.

Yes, I noticed that. But it doesn't appear in the .d.ts file, which is read by the TS compiler...

[Tymek]

Ok, I found the root cause. I'll work on a solution. It's not about noImplicitAny, but about skipLibCheck.

[tlevesque-ueat]

@Tymek thanks!
Indeed, that works for me.
If you can figure out a way to make that unnecessary, even better! (your PR looks promising, but I'm not really a TS/JS expert...)

[tlevesque-ueat]

It's not about noImplicitAny, but about skipLibCheck.

Actually, I think it's both. The error will occur if skipLibCheck is false (which is the default) AND noImplicitAny is true.
Setting noImplicitAny to false also fixed the problem for me (but I don't want to, since it also applies to my own code).
Setting skipLibCheck to true is probably the best workaround, with no real downside, since I don't care about checking the types in my dependencies...

[Tymek]

Thanks a lot for reproducible example. It helped a lot, and will become a part of our tests.

[Tymek]

Shipped in latest (v6.4.4)

[tlevesque-ueat]

Thanks for the fix!
Does that mean that with the latest version, I don't need the workarounds (declare module or skipLibCheck)?