fix: moveMultipleConnections edit COMPASS-10008

[paula-stacho]

Description

Saving multiple connections move.
Steps to Reproduce

• Create a diagram with multiple collections
• Select one collection
• Without unselecting, press down CMD button (on macos) and now try dragging another collection

These steps are a bit inconvenient, I think we might add proper support multi-item selections (the relational migrator has it), but that's for another day. This just fixes the issue that the users were able to drag multiple collections, but we weren't saving it.

Screen.Recording.2025-12-12.at.19.52.29.mov

Checklist

• New tests and/or benchmarks are included
• Documentation is changed or added
• If this change updates the UI, screenshots/videos are added and a design review is requested
• If this change could impact the load on the MongoDB cluster, please describe the expected and worst case impact
• I have signed the MongoDB Contributor License Agreement (https://www.mongodb.com/legal/contributor-agreement)

Motivation and Context

• Bugfix
• New feature
• Dependency update
• Misc

Open Questions

Dependents

Types of changes

• Backport Needed
• Patch (non-breaking change which fixes an issue)
• Minor (non-breaking change which adds functionality)
• Major (fix or feature that would cause existing functionality to change)

[Copilot]

Pull request overview

This PR fixes a bug where moving multiple collections simultaneously in the diagram editor was not being saved. The fix adds support for a new MoveMultipleCollections edit type that can handle batch position updates when users drag multiple selected collections.

Key Changes:

• Introduces a new MoveMultipleCollections edit type to handle batch collection moves
• Updates the diagram editor to detect multi-node drags and dispatch the appropriate edit action
• Adds schema validation and test coverage for the new edit type

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
packages/compass-data-modeling/src/store/diagram.ts	Adds moveMultipleCollections action creator for the new edit type
packages/compass-data-modeling/src/store/diagram.spec.ts	Adds test coverage for the MoveMultipleCollections edit functionality
packages/compass-data-modeling/src/store/apply-edit.ts	Implements the logic to apply MoveMultipleCollections edits to the model
packages/compass-data-modeling/src/services/data-model-storage.ts	Adds Zod schema validation for the new edit type
packages/compass-data-modeling/src/components/diagram-editor.tsx	Updates UI component to handle multi-node drag events and dispatch appropriate actions

[Copilot]

Use a for-of loop over Object.keys() for better readability and consistency with modern JavaScript patterns. Consider: for (const ns of Object.keys(edit.newPositions)) to eliminate the intermediate variable.

[Copilot]

Using includes() inside a map() results in O(n*m) complexity. Convert movedCollections to a Set before the map operation for O(1) lookup performance when dealing with multiple collections.

Suggested change

	for (const ns of movedCollections) {
	assertCollectionExists(model.collections, ns);
	}
	return {
	...model,
	collections: model.collections.map((collection) => {
	if (movedCollections.includes(collection.ns)) {
	const movedCollectionsSet = new Set(movedCollections);
	for (const ns of movedCollections) {
	assertCollectionExists(model.collections, ns);
	}
	return {
	...model,
	collections: model.collections.map((collection) => {
	if (movedCollectionsSet.has(collection.ns)) {