Add public setUniqueIdGenerator for custom ID generation

[theop-luma]

Summary

• Adds setUniqueIdGenerator as a public export from @tldraw/utils, allowing apps to customize how IDs are generated across tldraw (shapes, pages, records)
• Adds @tldraw/utils to the pack-and-copy.sh script so the tarball is available for downstream apps
• Re-exported via @tldraw/editor's export * from '@tldraw/utils'

Usage

import { setUniqueIdGenerator } from '@tldraw/editor'

setUniqueIdGenerator(() => `id-${Date.now()}-${Math.random()}`)

Note for vespa-web

After merging, add this override to frontend/vespa-web/package.json:

"@tldraw/utils": "file:../../shared/js/tldraw/tldraw-utils-4.4.0.tgz"

🤖 Generated with Claude Code

[cursor]

PR Summary

Medium Risk
Exposes a new global override for ID generation; misuse could lead to collisions or non-deterministic behavior across persisted records, but the change is small and localized.

Overview
Adds a new public setUniqueIdGenerator API in @tldraw/utils to allow apps to override the function used by uniqueId() at runtime.

Updates the utils public surface (API report + packages/utils/src/index.ts export) and adjusts scripts/pack-and-copy.sh to include the utils tarball in downstream packaging workflows.

^{Written by Cursor Bugbot for commit 544f5ec. This will update automatically on new commits. Configure here.}

[cursor]

Cursor Bugbot has reviewed your changes and found 2 potential issues.

Bugbot Autofix prepared fixes for both issues found in the latest run.

• ✅ Fixed: restoreUniqueId silently discards custom generator set via public API
  • I introduced a persistent configured generator baseline and changed restoreUniqueId to restore to that baseline instead of always restoring to nanoid.
• ✅ Fixed: New setUniqueIdGenerator duplicates existing mockUniqueId implementation
  • I removed the duplicated assignment logic by introducing a shared internal setter used by both setUniqueIdGenerator and mockUniqueId.

Or push these changes by commenting:

@cursor push 4883ac7764

Preview (4883ac7764)

diff --git a/packages/utils/src/lib/id.ts b/packages/utils/src/lib/id.ts
--- a/packages/utils/src/lib/id.ts
+++ b/packages/utils/src/lib/id.ts
@@ -54,8 +54,13 @@
 	return id
 }
 
-let impl = nanoid
+let configuredImpl = nanoid
+let impl = configuredImpl
 
+function setImpl(fn: (size?: number) => string) {
+	impl = fn
+}
+
 /**
  * Override the unique ID generator with a custom implementation.
  *
@@ -72,7 +77,8 @@
  * @public
  */
 export function setUniqueIdGenerator(fn: (size?: number) => string) {
-	impl = fn
+	configuredImpl = fn
+	setImpl(fn)
 }
 
 /**
@@ -95,13 +101,13 @@
  * @internal
  */
 export function mockUniqueId(fn: (size?: number) => string) {
-	impl = fn
+	setImpl(fn)
 }
 
 /**
- * Restore the original unique ID generator after mocking.
+ * Restore the configured unique ID generator after mocking.
  *
- * Resets the ID generation function back to the original nanoid implementation.
+ * Resets the ID generation function back to the currently configured implementation.
  * This should be called after testing to restore normal ID generation behavior.
  *
  * @example
@@ -116,7 +122,7 @@
  * @internal
  */
 export function restoreUniqueId() {
-	impl = nanoid
+	setImpl(configuredImpl)
 }
 
 /**

[cursor]

restoreUniqueId silently discards custom generator set via public API

Medium Severity

setUniqueIdGenerator sets impl to a custom function, but restoreUniqueId always resets impl back to the hard-coded nanoid, not to whatever was set via setUniqueIdGenerator. If a downstream app configures a custom generator and any code later calls restoreUniqueId, the custom generator is silently lost. restoreUniqueId needs to be aware of the user-configured baseline to restore to the right implementation.

Additional Locations (1)

• packages/utils/src/lib/id.ts#L117-L120