fix: emit valid JS for DestructuredArg with only a rest field

[FarhanAliRaza]

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• Bug fix (non-breaking change which fixes an issue)

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closes #6443

[greptile-apps]

Greptile Summary

This PR fixes DestructuredArg.to_javascript() to emit valid JavaScript when fields is empty and only a rest element is present — previously producing {, ...rest} instead of {...rest}. Two regression tests are added to cover both component-returning and var-returning memo variants, and an existing test's monkeypatch targets are corrected from compiler.utils to the explicitly imported compiler_utils alias.

Confidence Score: 5/5

Safe to merge — minimal, well-targeted fix with regression tests covering all affected code paths.

The change is a single-method, two-branch fix that handles all four combinations of empty/non-empty fields and present/absent rest. The new tests directly assert both the correct output and the absence of the previously broken form. No other logic is touched.

No files require special attention.

Important Files Changed

Filename	Overview
packages/reflex-base/src/reflex_base/vars/function.py	Fixes DestructuredArg.to_javascript() to omit the leading comma when fields is empty and only a rest element is present, preventing invalid JS like {, ...rest}.
tests/units/experimental/test_memo.py	Adds two regression tests for rest-only memo args, and corrects monkeypatch targets from compiler.utils to the already-imported compiler_utils alias for the existing import-remerging test.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A["DestructuredArg.to_javascript()"] --> B{"fields non-empty?"}
    B -- Yes --> C["inner = ', '.join(fields)"]
    B -- No --> D["inner = ''"]
    C --> E{"rest set?"}
    D --> E
    E -- Yes, inner non-empty --> F["inner = '{inner}, ...{rest}'"]
    E -- Yes, inner empty --> G["inner = '...{rest}'"]
    E -- No --> H["inner unchanged"]
    F --> I["return wrap(inner, '{', '}')"]
    G --> I
    H --> I
    I --> J["Result: valid JS\ne.g. {a, b, ...rest} or {...rest} or {a, b} or {}"]

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_{Reviews (1): Last reviewed commit: "fix: emit valid JS for DestructuredArg w..." | Re-trigger Greptile}

[codspeed-hq]

Merging this PR will not alter performance

✅ 17 untouched benchmarks
⏩ 2 skipped benchmarks¹

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_{Comparing FarhanAliRaza:fix-syntax-rxprops (4044c1c) with main (70ab07e)}

Footnotes

1. 2 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩