Add alpha splice method to TreeArrayNode

[brrichards]

Summary

Adds splice method to a new alpha TreeArrayNode interface, TreeArrayNodeAlpha, that follows Array.prototype.splice semantics. Supports removing and inserting items in a single opertaion, with optional deleteCount and negative start indices. Wraps remove + insert in a transaction for hydrated nodes to enable atomic undo/redo. Users opt into using the new api by doing asAlpha(<TreeArrayNode>) which then allows them to use splice and also still interact with other non-alpha TreeArrayNodes

[Copilot]

Pull request overview

Adds a new splice API to TreeArrayNode to support combined remove/insert operations with Array.prototype.splice-like behavior, including negative start indices and optional deleteCount, and updates the public API surface accordingly.

Changes:

• Adds TreeArrayNode.splice to the public interface and implements it in arrayNode.ts (wrapping hydrated edits in a transaction).
• Adds unit tests covering several splice scenarios.
• Updates API reports and adds a changeset entry documenting the new API.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
packages/dds/tree/src/test/simple-tree/node-kinds/arrayNode.spec.ts	Adds new splice test cases for array nodes
packages/dds/tree/src/simple-tree/node-kinds/array/arrayNode.ts	Adds splice to the interface and implements the method
packages/dds/tree/api-report/tree.public.api.md	Updates public API report to include splice
packages/dds/tree/api-report/tree.legacy.public.api.md	Updates legacy public API report to include splice
packages/dds/tree/api-report/tree.legacy.beta.api.md	Updates legacy beta API report to include splice
packages/dds/tree/api-report/tree.beta.api.md	Updates beta API report to include splice
packages/dds/tree/api-report/tree.alpha.api.md	Updates alpha API report to include splice
.changeset/plain-tires-melt.md	Adds a minor changeset describing the new splice method and usage

[jzaffiro]

Small nit but approved for docs

[CraigMacomber]

Despite having approval from an API Reviewer, this has not been api reviewed (GitHub doesn't let people approve for a subset of their review groups), so I'm going to use my requesting of changes as a placeholder for the need for an API review. If approving for API review, feel free to dismiss this.

[noencke]

Implementation looks good to me

[noencke]

Is there any way to avoid this cast? My guess is no, but curious what @CraigMacomber thinks

[Abe27342]

Did not review the tree code.

Approving for merge-tree, which doesn't actually have any changes we care about in this PR. Talked with Brennan offline and this is probably just a sticky GH check.

Also approving for API council as the PR contains only alpha API changes. I can see that this is also a sticky check from a previous revision that touched more broadly visible API files.

Api, tree, and docs approval received after Api moved from public to alpha

[github-actions]

🔗 No broken links found! ✅

Your attention to detail is admirable.

linkcheck output

> fluid-framework-docs-site@0.0.0 ci:check-links /home/runner/work/FluidFramework/FluidFramework/docs
> start-server-and-test "npm run serve -- --no-open" 3000 check-links

1: starting server using command "npm run serve -- --no-open"
and when url "[ 'http://127.0.0.1:3000' ]" is responding with HTTP status code 200
running tests using command "npm run check-links"


> fluid-framework-docs-site@0.0.0 serve
> docusaurus serve --no-open

[SUCCESS] Serving "build" directory at: http://localhost:3000/

> fluid-framework-docs-site@0.0.0 check-links
> linkcheck http://localhost:3000 --skip-file skipped-urls.txt

Crawling...

Stats:
  272172 links
    1863 destination URLs
    2108 URLs ignored
       0 warnings
       0 errors