Site editor: preset custom color duplicates (#40837)

* Initial commit
Check the slugs for the highest id number and add one.

* Ensure that color option keys are unique, even where colors are the same

* Updating test snapshots
Adding tests for getNameForPosition()

* Roll back unique keys test

* Update packages/components/src/palette-edit/index.js

Update doc comments

Co-authored-by: Glen Davies <glendaviesnz@users.noreply.github.com>

* Extra tests

Co-authored-by: Glen Davies <glendaviesnz@users.noreply.github.com>

packages/components/src/palette-edit/index.js

@@ -56,11 +56,36 @@ function NameInput( { value, onChange, label } ) {
 	);
 }
 
-function getNameForPosition( position ) {
+/**
+ * Returns a temporary name for a palette item in the format "Color + id".
+ * To ensure there are no duplicate ids, this function checks all slugs for temporary names.
+ * It expects slugs to be in the format: slugPrefix + color- + number.
+ * It then sets the id component of the new name based on the incremented id of the highest existing slug id.
+ *
+ * @param {string} elements   An array of color palette items.
+ * @param {string} slugPrefix The slug prefix used to match the element slug.
+ *
+ * @return {string} A unique name for a palette item.
+ */
+export function getNameForPosition( elements, slugPrefix ) {
+	const temporaryNameRegex = new RegExp( `^${ slugPrefix }color-([\\d]+)$` );
+	const position = elements.reduce( ( previousValue, currentValue ) => {
+		if ( typeof currentValue?.slug === 'string' ) {
+			const matches = currentValue?.slug.match( temporaryNameRegex );
+			if ( matches ) {
+				const id = parseInt( matches[ 1 ], 10 );
+				if ( id >= previousValue ) {
+					return id + 1;
+				}
+			}
+		}
+		return previousValue;
+	}, 1 );
+
 	return sprintf(
 		/* translators: %s: is a temporary id for a custom color */
-		__( 'Color %s ' ),
-		position + 1
+		__( 'Color %s' ),
+		position
 	);
 }
 
@@ -163,9 +188,10 @@ function Option( {
 	);
 }
 
-function isTemporaryElement( slugPrefix, { slug, color, gradient }, index ) {
+function isTemporaryElement( slugPrefix, { slug, color, gradient } ) {
+	const regex = new RegExp( `^${ slugPrefix }color-([\\d]+)$` );
 	return (
-		slug === slugPrefix + kebabCase( getNameForPosition( index ) ) &&
+		regex.test( slug ) &&
 		( ( !! color && color === DEFAULT_COLOR ) ||
 			( !! gradient && gradient === DEFAULT_GRADIENT ) )
 	);
@@ -193,8 +219,7 @@ function PaletteEditListView( {
 				)
 			) {
 				const newElements = elementsReference.current.filter(
-					( element, index ) =>
-						! isTemporaryElement( slugPrefix, element, index )
+					( element ) => ! isTemporaryElement( slugPrefix, element )
 				);
 				onChange( newElements.length ? newElements : undefined );
 			}
@@ -309,8 +334,10 @@ export default function PaletteEdit( {
 							}
 							onClick={ () => {
 								const tempOptionName = getNameForPosition(
-									elementsLength
+									elements,
+									slugPrefix
 								);
+
 								onChange( [
 									...elements,
 									{

packages/components/src/palette-edit/test/index.js

@@ -0,0 +1,63 @@
+/**
+ * Internal dependencies
+ */
+import { getNameForPosition } from '../';
+
+describe( 'getNameForPosition', () => {
+	test( 'should return 1 by default', () => {
+		const slugPrefix = 'test-';
+		const elements = [];
+
+		expect( getNameForPosition( elements, slugPrefix ) ).toEqual(
+			'Color 1'
+		);
+	} );
+
+	test( 'should return a new color name with an incremented slug id', () => {
+		const slugPrefix = 'test-';
+		const elements = [
+			{
+				slug: 'test-color-1',
+			},
+		];
+
+		expect( getNameForPosition( elements, slugPrefix ) ).toEqual(
+			'Color 2'
+		);
+	} );
+
+	test( 'should ignore user-defined color names', () => {
+		const slugPrefix = 'test-';
+		const elements = [
+			{
+				slug: 'a-sweet-color-2',
+			},
+		];
+
+		expect( getNameForPosition( elements, slugPrefix ) ).toEqual(
+			'Color 1'
+		);
+	} );
+
+	test( 'should return a new color name with an incremented slug id one higher than the current highest', () => {
+		const slugPrefix = 'test-';
+		const elements = [
+			{
+				slug: 'test-color-1',
+			},
+			{
+				slug: 'test-color-2',
+			},
+			{
+				slug: 'test-color-150',
+			},
+			{
+				slug: 'a-sweet-color-100',
+			},
+		];
+
+		expect( getNameForPosition( elements, slugPrefix ) ).toEqual(
+			'Color 151'
+		);
+	} );
+} );