add(watchKeepAlive) that only triggers when keep alive component active.

[prochorz]

• [x] Read the Contributing Guidelines.
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• [x] Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
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• [x] Ideally, include relevant tests that fail without this PR but pass with it.

⚠️ Slowing down new functions

Warning: Slowing down new functions

As the VueUse audience continues to grow, we have been inundated with an overwhelming number of feature requests and pull requests. As a result, maintaining the project has become increasingly challenging and has stretched our capacity to its limits. As such, in the near future, we may need to slow down our acceptance of new features and prioritize the stability and quality of existing functions. Please note that new features for VueUse may not be accepted at this time. If you have any new ideas, we suggest that you first incorporate them into your own codebase, iterate on them to suit your needs, and assess their generalizability. If you strongly believe that your ideas are beneficial to the community, you may submit a pull request along with your use cases, and we would be happy to review and discuss them. Thank you for your understanding.

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Description

watchKeepAlive that only triggers when keep alive component active.

Additional context

The callback function is only triggered when the keep-alive component is active.

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🤖 Generated by Copilot at f933564

This pull request adds a new utility function watchKeepAlive to the shared package, which allows watching reactive sources only when the component is kept alive by a keep-alive component. It also adds documentation and tests for the function.

🤖 Generated by Copilot at f933564

• Export watchKeepAlive function from shared package (link)
• Implement watchKeepAlive function to create a reactive effect that is only active when the component is kept alive (link)
• Document watchKeepAlive function with usage and API details in watchKeepAlive/index.md (link)
• Test watchKeepAlive function with vitest framework in watchKeepAlive/index.test.ts (link)

[antfu]

Can you explain a bit more about the use case about this function? Thanks

[Alfred-Skyblue]

When keepAlive is in the deactivated state, the watch inside the component is still active. If the dependent reactive variable changes at this time, the execution of watch will still be triggered. I think it should be solved by vue. I opened a pr #9206 in vue, but currently only the render function is processed. At present, watch, computed, etc. are not processed. Maybe keepAlive should pause EffectScope in the deactivated state.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.