Nav block: enable creation from existing WP Menus

packages/block-library/src/navigation/create-data-tree.js

@@ -0,0 +1,39 @@
+/**
+ * Creates a nested, hierarchical tree representation from unstructured data that
+ * has an inherent relationship defined between individual items.
+ *
+ * For example, by default, each element in the dataset should have an `id` and
+ * `parent` property where the `parent` property indicates a relationship between
+ * the current item and another item with a matching `id` properties.
+ *
+ * This is useful for building linked lists of data from flat data structures.
+ *
+ * @param {Array} dataset linked data to be rearranged into a hierarchical tree based on relational fields.
+ * @param {string} id the property which uniquely identifies each entry within the array.
+ * @param {*} relation the property which identifies how the current item is related to other items in the data (if at all).
+ * @return {Array} a nested array of parent/child relationships
+ */
+function createDataTree( dataset, id = 'id', relation = 'parent' ) {
+	const hashTable = Object.create( null );
+	const dataTree = [];
+
+	for ( const data of dataset ) {
+		hashTable[ data[ id ] ] = {
+			...data,
+			children: [],
+		};
+	}
+	for ( const data of dataset ) {
+		if ( data[ relation ] ) {
+			hashTable[ data[ relation ] ].children.push(
+				hashTable[ data[ id ] ]
+			);
+		} else {
+			dataTree.push( hashTable[ data[ id ] ] );
+		}
+	}
+
+	return dataTree;
+}
+
+export default createDataTree;