fix(NG & WC): attribute passing removals

[mfranzke]

Description

Please provide the following information:

What changes you made:

Fix (in attribute-passing.ts, 2 lines changed):

1. const attributes = parent.attributes; → const attributes = [...parent.attributes]; — creates a static snapshot before iterating
2. const attr = attributes.item(i); → const attr = attributes[i]; — uses standard array indexing on the now-static array

Test (new file attribute-passing.test.ts):

• Uses a Proxy-based mock that faithfully simulates the live NamedNodeMap behavior (length/indexing reflect mutations in real time)
• Evaluates the actual generated runtime code via new Function against the mock DOM
• Verifies the exact reproduction case (data-a="1" data-b="2") plus aria, class, mixed attributes, and 3+ data attributes
• Confirmed: the test fails with the old code (4/5 tests fail) and passes with the fix (5/5 pass)

Why you made them, and:

The enableAttributePassing runtime code iterated over parent.attributes (a live NamedNodeMap) while calling parent.removeAttribute() inside the loop. Since NamedNodeMap is a live collection, removing an attribute shrinks it mid-iteration, causing subsequent attributes to be skipped.

Any other useful context:

Make sure to follow the PR preparation steps in CONTRIBUTING.md before submitting your PR:

• format the codebase: from the root, run yarn fmt:prettier.
• update all snapshots (in core & CLI): from the root, run yarn test:update
• add Changeset entry: from the root, run yarn g:changeset and follow the CLI instructions. Alternatively, use the Changeset Github Bot to create the file.

[changeset-bot]

🦋 Changeset detected

Latest commit: 081862c

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@builder.io/mitosis	Patch
@builder.io/mitosis-cli	Patch

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☁️ Nx Cloud last updated this comment at 2026-07-20 14:54:43 UTC