fix: correct behavior for focusable-less targets. Implements #41

.gitignore

@@ -1,4 +1,5 @@
 node_modules/
 npm-debug.log
 /dist/
-.DS_Store
+.DS_Store
+coverage

__tests__/focusMerge.spec.ts

@@ -110,5 +110,15 @@ describe('FocusMerge', () => {
 
       expect(focusMerge(querySelector('#d1'), null)!.node.innerHTML).toBe('1');
     });
+
+    it('autofocus - nothing to focus', () => {
+      document.body.innerHTML = `    
+        <div id="d1">         
+        <button disabled>1</button>        
+        </div>    
+    `;
+
+      expect(focusMerge(querySelector('#d1'), null)!).toBe(undefined);
+    });
   });
 });

src/focusMerge.ts

@@ -49,7 +49,15 @@ export const getFocusMerge = (
   const newId = newFocus(innerNodes, outerNodes, activeElement, lastNode as HTMLElement);
 
   if (newId === NEW_FOCUS) {
-    return { node: pickAutofocus(anyFocusable, innerNodes, allParentAutofocusables(entries, visibilityCache)) };
+    const focusNode = pickAutofocus(anyFocusable, innerNodes, allParentAutofocusables(entries, visibilityCache));
+
+    if (focusNode) {
+      return { node: focusNode };
+    } else {
+      console.warn('focus-lock: cannot find any node to move focus into');
+
+      return undefined;
+    }
   }
 
   if (newId === undefined) {

src/utils/auto-focus.ts

@@ -22,7 +22,7 @@ export const pickAutofocus = (
   nodesIndexes: NodeIndex[],
   orderedNodes: HTMLElement[],
   groups: Element[]
-): HTMLElement => {
+): HTMLElement | undefined => {
   const nodes = nodesIndexes.map(({ node }) => node);
 
   const autoFocusable = filterAutoFocusable(nodes.filter(findAutoFocused(groups)));

src/utils/firstFocus.ts

@@ -1,6 +1,6 @@
 import { correctNode } from './correctFocus';
 
-export const pickFirstFocus = (nodes: HTMLElement[]): HTMLElement => {
+export const pickFirstFocus = (nodes: HTMLElement[]): HTMLElement | undefined => {
   if (nodes[0] && nodes.length > 1) {
     return correctNode(nodes[0], nodes);
   }