Description

Objective: Because breaking changes for TypeScript 6.0 are compatible with TypeScript 5.9 and especially because no compile errors, fix prerequisites now so upgrade contribution in a few weeks will be easy.

https://devblogs.microsoft.com/typescript/announcing-typescript-6-0-beta/

TypeScript 6.0 is a unique release in that we intend for it to be the last release based on the current JavaScript codebase.

Most changes in TypeScript 6.0 are meant to help align and prepare for adopting TypeScript 7.0.

Configuration errors

tsconfig.json:9:5 - error TS5101: Option 'baseUrl' is deprecated and will stop functioning in TypeScript 7.0. Specify compilerOption '"ignoreDeprecations": "6.0"' to silence this error.

9     "baseUrl": "src",

tsconfig.json:20:25 - error TS5107: Option 'moduleResolution=node10' is deprecated and will stop functioning in TypeScript 7.0. Specify compilerOption '"ignoreDeprecations": "6.0"' to silence this error.

20     "moduleResolution": "node",

Configuration changes

https://devblogs.microsoft.com/typescript/announcing-typescript-6-0-beta/#breaking-changes-and-deprecations-in-typescript-6.0

1. Delete deprecated baseUrl property.

   The baseUrl option is most-commonly used in conjunction with paths, and is typically used as a prefix for every value in paths. Unfortunately, baseUrl is also considered a look-up root for module resolution.

   In the best case, this also often leads to "worse-looking" paths that bundlers would ignore; but it often meant that that many import paths that would never have worked at runtime are considered "just fine" by TypeScript.

2. Add paths property as declarative replacement for what baseUrl had done.

   Path mappings have not required specifying baseUrl for a long time, and in practice, most projects that use baseUrl only use it as a prefix for their paths entries. In TypeScript 6.0, baseUrl is deprecated and will no longer be considered a look-up root for module resolution.

   Developers who used baseUrl as a prefix for path-mapping entries can simply remove baseUrl and add the prefix to their paths entries.

3. Replace module and moduleResolution properties to fix 36 occurrences of TS2307 error for dynamic import paths in Body.tsx file.

   Cannot find module 'x' or its corresponding type declarations

   improperly configured tsconfig.json path aliases

   Specifically, "moduleResolution": "bundler" which is accurate.

   Bonus "module": "es2020" is specific to what this project assumes.

4. Add rootDir property.

   rootDir controls the directory structure of your output files relative to the output directory. Previously, if you did not specify a rootDir, it was inferred based on the common directory of all non-declaration input files. But this often meant that it was impossible to know if a file belonged to a project without trying to load and parse that project. It also meant that TypeScript had to spend more time inferring that common source directory by analyzing every file path in the program.

   Set "rootDir": "./src" if you were previously relying on this being inferred.

   Although TypeScript does not output files in this project, if I understand correctly, it might waste time inferring.

5. Edit include property to simplify the path.

   Follow examples in documentation that I read to understand other changes.

User-facing documentation

• CHANGELOG.md update is not needed
• documentation PR is not needed

Testing and quality

• the change is production ready: the change is GA, or otherwise the functionality is gated by a feature flag
• CI results are inspected

Automated testing

• added unit tests
• added e2e tests
• added regression tests
• added compatibility tests
• modified existing tests

How I validated my change

1. npm run tsc in ui/apps/platform folder.
2. npm run lint:fast-dev in ui/apps/platform folder.
3. npm run start in ui/apps/platform folder with staging demo as central.
4. npm build in ui/apps/platform folder.