Refactor (packages/web/src/components/Share.tsx:503): High complexity function fromV1

[slaman24]

P1B: Starter Task: Refactoring PR

1. Issue

Link to the associated GitHub issue: #94

Full path to the refactored file: packages/web/src/components/Share.tsx

What do you think this file does?
(Your answer does not have to be 100% correct; give a reasonable, evidence‑based guess.)
I believe this file displays a shared session on the web page. Specifically, the fromV1 function is responsible for converting old v1 message records into the new v2 format that the renderer expects.

What is the scope of your refactoring within that file?
(Name specific functions/blocks/regions touched.)
Refactored fromV1 by extracting its nested role/part-type/tool-state branching into five new helper functions: fromV1Assistant, toAssistantParts, toToolState, fromV1User, and toUserParts

Which Qlty‑reported issue did you address?
(Name the rule/metric and include the BEFORE value; e.g., “Cognitive Complexity 18 in render()”.)
High complexity (count = 32) in function fromV1

2. Refactoring

How did the specific issue you chose impact the codebase’s maintainability?
The role → part-type → tool-state branching was packed all into one ~140-line function with 4 levels of nesting. This made the code harder to read and more challenging to safely modify one case without risking the others.

What changes did you make to resolve the issue?
I extracted each level of nested branching into its own small, named function, turning fromV1 from a ~140-line function to a 3-line one (with no behavior change).

How do your changes improve maintainability? Did you consider alternatives?
Each helper now handles exactly one concern and can be read and modified independently. I originally considered simplifying the nested branching but still keeping all of the code within fromV1, but I ultimately felt that dividing the code into helper functions would increase the overall readability.

3. Validation

How did you validate that the change is correct?
I wrote 7 unit tests that call fromV1 directly and cover every branch (both roles, all 3 tool-invocation states, both handled part types, the unhandled-part-type fallback, and both throw paths), confirmed 100% line coverage of the changed code, and ran qlty smells --no-snippets packages/web/src/components/Share.tsx to confirm that the high complexity warning was gone with no new warnings introduced.

Attach a screenshot of the test coverage showing the lines were executed by the tests.

Per-function line coverage for fromV1 and its extracted helpers. 139/139 lines (100%) executed by tests.

Running bunx oxlint on the changed files shows 0 warnings and 0 errors.

Attach a screenshot showing the tests that cover the change passing during CI

All 7 unit tests for fromV1 pass during CI.

Attach a screenshot of qlty smells --no-snippets <full/path/to/file.ts> showing fewer reported issues after the changes.

After implementing my code changes, running qlty smells --no-snippets packages/web/src/components/Share.tsx no longer reports 503 Function with high complexity (count = 32): fromV1