fix(ESM): support mts and cts files

[Kampfmoehre]

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• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Have you written unit tests?
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• This PR is associated with an existing issue? Missing ECMAScript modules (ESM) support in both controller search and routes generation #1307

Closing issues
#1307

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• Has the issue had a maintainer respond to the issue and clarify that the feature is something that aligns with the goals and philosophy of the project?

Potential Problems With The Approach

Haven't had the ability to also test .cts files but I think this should be straight forward.

Test plan

I added two unit tests for the route generator method getRelativeImportPath that replaces the extension in controller files.

[WoH]

Does it hurt to add these in case we are CJS?

[Kampfmoehre]

I don't think it hurts. As far as I know you have 3 possible ways to work with ESM in TypeScript:

• keep ts files
• use mts files when you want to output specifically ESM files
• use cts files when you also want to output CommonJS

For our use case we only need mts/mjs files, but the logic is the same for the others as far as I know.
For reference: https://www.typescriptlang.org/docs/handbook/esm-node.html#new-file-extensions