[chai] Add proper AssertionError export

[MysteryBlokHed]

Related discussion: #73706

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[typescript-bot]

@MysteryBlokHed Thank you for submitting this PR!

This is a live comment that I will keep updated.

2 packages in this PR

• bardjs — on npm, on unpkg
• chai — on npm, on unpkg

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---

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[typescript-bot]

🔔 @Bartvds @AGBrown @olivr70 @mwistrand @shaunluttin @micksatana @ErikSchierboom @bparan @CXuesong @joeykilpatrick — please review this PR in the next few days. Be sure to explicitly select Approve or Request Changes in the GitHub UI so I know what's going on.

[typescript-bot]

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[typescript-bot]

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[typescript-bot]

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[jakebailey]

Why not just a plain reexport?

[MysteryBlokHed]

I didn't seem to be able to re-export it like this (when importing as import { AssertionError } from "assertion-error"), since it caused type errors elsewhere:

        export { AssertionError };

Which is why I wrote it the way I did.

This Chai namespace also doesn't seem to exist at runtime, and it only defines types; everything other than this AssertionError class is an interface or type alias. So just exporting the type of AssertionError seemed to make sense to me

[jakebailey]

The errors would be helpful to look at, though it is interesting that this is used for the type only namespace, but you noted that the real package depended on it. I do wonder how these types are intended to be used?

[MysteryBlokHed]

The class is also re-exported by the chai library and available at runtime, which I've represented in the types:

export const AssertionError: typeof ImportedAssertionError;

I also updated the type in the Chai namespace, but that wasn't the main purpose of the PR. The original discussion was specifically about the type definitions not indicating that AssertionError is directly exported by chai: #73706

[MysteryBlokHed]

Also, for reference, here are the errors I get from pnpm test chai if I try to change the way I export the type in the namespace:

--- a/types/chai/index.d.ts
+++ b/types/chai/index.d.ts
@@ -2129,7 +2129,7 @@ declare global {
             deepEqual: <L, R>(expected: L, actual: R) => void;
         }
 
-        export type AssertionError = typeof ImportedAssertionError;
+        export { ImportedAssertionError as AssertionError };
     }
 }
 

$ pnpm test chai

> definitely-typed@0.0.3 test /home/adam/Git/DefinitelyTyped
> node --enable-source-maps node_modules/@definitelytyped/dtslint/ types "chai"

dtslint@0.2.34
Error:
/home/adam/Git/DefinitelyTyped/types/chai/chai-tests.ts
   783:36  error  TypeScript@5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 compile error:
Namespace 'global.Chai' has no exported member 'ChaiStatic'                     @definitelytyped/expect
   783:60  error  TypeScript@5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 compile error:
Namespace 'global.Chai' has no exported member 'ChaiUtils'                      @definitelytyped/expect
   788:39  error  TypeScript@5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 compile error:
'this' implicitly has type 'any' because it does not have a type annotation     @definitelytyped/expect
   792:17  error  TypeScript@5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 compile error:
'this' implicitly has type 'any' because it does not have a type annotation     @definitelytyped/expect
   803:39  error  TypeScript@5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 compile error:
'this' implicitly has type 'any' because it does not have a type annotation     @definitelytyped/expect
   807:17  error  TypeScript@5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 compile error:
'this' implicitly has type 'any' because it does not have a type annotation     @definitelytyped/expect
   818:51  error  TypeScript@5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 compile error:
'global.Chai' has no exported member named 'Assertion'. Did you mean 'Assert'?  @definitelytyped/expect
   878:52  error  TypeScript@5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 compile error:
Namespace 'global.Chai' has no exported member 'ChaiStatic'                     @definitelytyped/expect
   878:76  error  TypeScript@5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 compile error:
Namespace 'global.Chai' has no exported member 'ChaiUtils'                      @definitelytyped/expect
   882:13  error  TypeScript@5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 compile error:
'this' implicitly has type 'any' because it does not have a type annotation     @definitelytyped/expect
  2236:26  error  TypeScript@5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 compile error:
Parameter 'expected' implicitly has an 'any' type                               @definitelytyped/expect
  2236:36  error  TypeScript@5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 compile error:
Parameter 'actual' implicitly has an 'any' type                                 @definitelytyped/expect

/home/adam/Git/DefinitelyTyped/types/chai/index.d.ts
  2136:30  error  TypeScript@5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 compile error:
Namespace 'global.Chai' has no exported member 'ChaiPlugin'  @definitelytyped/expect
  2136:48  error  TypeScript@5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 compile error:
Namespace 'global.Chai' has no exported member 'ChaiStatic'  @definitelytyped/expect
  2138:25  error  TypeScript@5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 compile error:
Namespace 'global.Chai' has no exported member 'ChaiUtils'   @definitelytyped/expect
  2142:32  error  TypeScript@5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 compile error:
Namespace 'global.Chai' has no exported member 'Should'      @definitelytyped/expect
  2143:32  error  TypeScript@5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0 compile error:
Namespace 'global.Chai' has no exported member 'Should'      @definitelytyped/expect

✖ 17 problems (17 errors, 0 warnings)

    at combineErrorsAndWarnings (/home/adam/Git/DefinitelyTyped/node_modules/.pnpm/@definitelytyped+dtslint@0.2.34_typescript@6.0.0-dev.20251003/node_modules/@definitelytyped/dtslint/src/index.ts:266:26)
    at runTests (/home/adam/Git/DefinitelyTyped/node_modules/.pnpm/@definitelytyped+dtslint@0.2.34_typescript@6.0.0-dev.20251003/node_modules/@definitelytyped/dtslint/src/index.ts:257:18)
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
    at async main (/home/adam/Git/DefinitelyTyped/node_modules/.pnpm/@definitelytyped+dtslint@0.2.34_typescript@6.0.0-dev.20251003/node_modules/@definitelytyped/dtslint/src/index.ts:103:22)
 ELIFECYCLE  Test failed. See above for more details.

[jakebailey]

Ah, adding export {} in a dts file disables implicit exports; if you explicitly add export to all of the types and such in the namespace, that would fix things.

I'm pretty sure this hasn't been caught because chai for some reason has disabled the eslint rule that notes when an export modifier doesn't mean anything.

[MysteryBlokHed]

Oh right, I forgot about that

I've added an explicit export to each of the interfaces and types. I also used export type {} for AssertionError instead of just export {}, since the Chai namespace doesn't exist at runtime

[typescript-bot]

@MysteryBlokHed The CI build failed! Please review the logs for more information.

Once you've pushed the fixes, the build will automatically re-run. Thanks!

Note: builds that are failing do not end up on the list of PRs for the DT maintainers to review.

[typescript-bot]

@jakebailey Thank you for reviewing this PR! The author has pushed new commits since your last review. Could you take another look and submit a fresh review?

[typescript-bot]

Re-ping @Bartvds, @AGBrown, @olivr70, @mwistrand, @shaunluttin, @micksatana, @ErikSchierboom, @bparan, @CXuesong, @joeykilpatrick:

This PR has been out for over a week, yet I haven't seen any reviews.

Could someone please give it some attention? Thanks!

[jakebailey]

Let's see how this goes...

[typescript-bot]

@MysteryBlokHed: Everything looks good here. I am ready to merge this PR (at bd3ca47) on your behalf whenever you think it's ready.

If you'd like that to happen, please post a comment saying:

Ready to merge

and I'll merge this PR almost instantly. Thanks for helping out! ❤️

[MysteryBlokHed]

Ready to merge