feat: add guard action for narrowing using type predicates

[EskiMojo14]

fixes #1089

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Name	Status	Preview	Comments	Updated (UTC)
valibot	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	May 26, 2025 8:33pm

[EskiMojo14]

leaving this as draft now as i can't work out how to allow type guards that accept wider types than the current pipe type

edit: switching back to the previous overloads half fixes the issue - it's now complaining when the output type is wider than the input type

[Copilot]

Pull Request Overview

This PR introduces a new guard action and corresponding type definitions to enable narrowing using type predicates in the transformation framework. Key changes include:

• Adding new API links and documentation for the guard action in markdown files.
• Defining and exporting new types and properties for GuardIssue and GuardAction across the API and type folders.
• Implementing the guard function in the library with associated tests covering functionality and type inference.

Reviewed Changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
website/src/routes/api/menu.md	Added menu links for guard and its related issues/actions.
website/src/routes/api/(types)/GuardIssue/*	Introduced new property definitions and documentation for GuardIssue.
website/src/routes/api/(types)/GuardAction/*	Added type properties and documentation for GuardAction.
website/src/routes/api/(actions)/guard/*	Created properties and docs for the guard action along with usage examples.
library/src/actions/guard/*	Implemented the guard function, interfaces, and tests ensuring correct behavior and type inference.

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commit: d4f4300

[fabian-hiller]

Thank you for working on this! I plan it for our v1.2 release. Feel free to mark it as ready once you are done. After that I will take over, review everything and merge it.

[EskiMojo14]

found a fix (involving lots of any, unfortunately, though only in positions where a more specific type will be kept later) - should be ready for review :)

[Copilot]

Pull request overview

Copilot reviewed 12 out of 12 changed files in this pull request and generated 6 comments.

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[fabian-hiller]

This PR should be ready now. I will merge it soon.

[Copilot]

Pull request overview

Copilot reviewed 101 out of 101 changed files in this pull request and generated 1 comment.