refactor(traverseFunctions.js): add traverseAncestors()

src/base/traverseFunctions.js

@@ -488,3 +488,28 @@ export function toggleTiles( tile, renderer ) {
 	}
 
 }
+
+/**
+ * Traverses the ancestry of the tile up to the root tile.
+ */
+export function traverseAncestors( tile, callback = null ) {
+
+	let current = tile;
+
+	while ( current ) {
+
+		const depth = current.__depth;
+		const parent = current.parent;
+
+		if ( callback ) {
+
+			callback( current, parent, depth );
+
+		}
+
+		current = parent;
+
+	}
+
+
+}

test/traverseFunctions.test.js

@@ -1,4 +1,4 @@
-import { traverseSet } from '../src/base/traverseFunctions.js';
+import { traverseAncestors, traverseSet } from '../src/base/traverseFunctions.js';
 
 describe( 'traverseSet', () => {
 
@@ -99,3 +99,30 @@ describe( 'traverseSet', () => {
 	} );
 
 } );
+
+describe( 'traverseAncestors', () => {
+
+	function makeTile( name, parent = undefined ) {
+
+		return { name, parent };
+
+	}
+
+	it( 'visit all ancestry chain', () => {
+
+		const root = makeTile( 'root' );
+
+		const lod1 = makeTile( '1', root );
+		const lod2 = makeTile( '2', lod1 );
+		const lod3 = makeTile( '3', lod2 );
+		const lod4 = makeTile( '4', lod3 );
+
+		const visited = [];
+
+		traverseAncestors( lod4, tile => visited.push( tile.name ) );
+
+		expect( visited ).toEqual( [ '4', '3', '2', '1', 'root' ] );
+
+	} );
+
+} );