fix(vue/valid-v-for): allow using an empty alias in value #2991
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🦋 Changeset detectedLatest commit: 3ea9630 The changes in this PR will be included in the next version bump. This PR includes changesets to release 1 package
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FloEdelmann
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Thank you for looking into it. Looks good to me 🙂
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Pull request overview
This PR fixes the vue/valid-v-for rule to correctly allow empty value aliases in v-for directives, such as v-for="(, key) in obj", which is valid Vue.js syntax when you only need the key/index from an iteration.
Key Changes:
- Updated validation logic to only report an error when both value and key are empty
- Added test cases for the newly allowed syntax patterns
- Removed incorrectly failing test case
Reviewed changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| lib/rules/valid-v-for.js | Modified the empty alias validation to allow empty value when a key is present |
| tests/lib/rules/valid-v-for.js | Added valid test cases for (, key) and (, key, index) patterns; removed false-positive invalid test |
| .changeset/silly-falcons-explain.md | Added changeset documenting the patch-level fix |
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| }, | ||
| { | ||
| filename: 'test.vue', | ||
| code: '<template><div><div v-for="(a,,b) in list"></div></div></template>', |
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This is also a valid syntax, we consider it as invalid since no one is actually using the object's index, right?
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If using the index makes sense, I wonder if invalidEmptyAlias was intentionally added to avoid potential errors. Maybe this rule recommends explicitly enumerating all variables before use (and pairing it with other rules to handle unused variables).
If that goes beyond this rule, I think cases like (value, , index), (value,,)or (, , index)—while valid syntax—should also be allowed. (or invalidEmptyAlias could just focus on cases like (value,,) where the alias is empty at the end)
Let me know what you guys think.
resolves #2733
This is indeed valid syntax.
See Vue Playground