fix(reactivity): update iterator to check for completion instead of value presence

[yangdan8]

…alue presence

Summary by CodeRabbit

• Bug Fixes
  • Fixed iteration behavior so falsy values (0, '', false) are now correctly handled during iteration, preserving reactivity updates.
  • Ensures consistent wrapping of non-final iteration results, improving stability in templates, computed values, and watchers; no public API changes.

[coderabbitai]

Walkthrough

Iterator wrapper in arrayInstrumentations now applies wrapValue whenever an iterator result is not done (i.e., checks !result.done), ensuring falsy values are wrapped; wrapping is skipped only for done: true. No public API or exported signatures changed.

Changes

Cohort / File(s)	Change Summary
Iterator wrapping logic packages/reactivity/src/arrayInstrumentations.ts	Replaced condition if (result.value) with if (!result.done) so wrapValue is invoked for all non-final iterator results (including falsy values); no wrapping when done is true. No public API changes.

Sequence Diagram(s)

sequenceDiagram
  autonumber
  participant User
  participant ReactiveArray
  participant Iterator
  participant wrapValue

  User->>ReactiveArray: for...of / iteration
  ReactiveArray->>Iterator: next()
  loop while not done
    Iterator-->>ReactiveArray: { value, done: false }
    Note over ReactiveArray,wrapValue: New behavior: wrap even falsy values\n(condition: !result.done)
    ReactiveArray->>wrapValue: wrap(value)
    wrapValue-->>ReactiveArray: wrappedValue
    ReactiveArray-->>User: wrappedValue
    ReactiveArray->>Iterator: next()
  end
  Iterator-->>ReactiveArray: { value, done: true }
  ReactiveArray-->>User: iteration ends (no wrapping)

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Pre-merge checks (3 passed)

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title Check	✅ Passed	The title succinctly and accurately summarizes the main change—switching the iterator check from inspecting the value to checking completion (done)—and uses the conventional-commit prefix (fix(reactivity):), making it clear and relevant to the changes in packages/reactivity/src/arrayInstrumentations.ts.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

Poem

I hop through loops with careful care,
Wrapping each nibble of value there—
Falsy or shiny, none are spared a coat,
Until “done” calls time and ends the note.
Carrot-debugged, I bound with glee.

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📜 Recent review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 8354e25 and 6b7468a.

📒 Files selected for processing (1)

• packages/reactivity/src/arrayInstrumentations.ts (1 hunks)

🚧 Files skipped from review as they are similar to previous changes (1)

• packages/reactivity/src/arrayInstrumentations.ts

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• Create PR with unit tests
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[edison1105]

Could you please add a test case?

[github-actions]

Size Report

Bundles

File	Size	Gzip	Brotli
runtime-dom.global.prod.js	101 kB (-1 B)	38.5 kB (-1 B)	34.6 kB (-2 B)
vue.global.prod.js	159 kB (-1 B)	58.6 kB (+1 B)	52.2 kB (+70 B)

Usages

Name	Size	Gzip	Brotli
createApp (CAPI only)	46.6 kB (-1 B)	18.2 kB (+1 B)	16.7 kB (-11 B)
createApp	54.6 kB (-1 B)	21.3 kB (+1 B)	19.5 kB (+13 B)
createSSRApp	58.9 kB (-1 B)	23 kB	21 kB
defineCustomElement	59.6 kB (-1 B)	22.8 kB (+1 B)	20.9 kB (+5 B)
overall	68.8 kB (-1 B)	26.4 kB (-1 B)	24.1 kB (-66 B)

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commit: 6b7468a