From f7aa7bfb2f6115029eecb04836da2f3e5510c0e3 Mon Sep 17 00:00:00 2001
From: Giampaolo Bellavite <gpbellavite@gmail.com>
Date: Mon, 5 Mar 2018 09:42:04 +0100
Subject: [PATCH 1/2] Return if node is not found

---
 src/DayPicker.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/DayPicker.js b/src/DayPicker.js
index 6fb17ceee1..c60af374ae 100644
--- a/src/DayPicker.js
+++ b/src/DayPicker.js
@@ -300,7 +300,7 @@ export default class DayPicker extends Component {
   focusPreviousDay(dayNode) {
     const dayNodes = Helpers.getDayNodes(this.dayPicker, this.props.classNames);
     const dayNodeIndex = Helpers.nodeListToArray(dayNodes).indexOf(dayNode);
-
+    if (dayNodeIndex === -1) return;
     if (dayNodeIndex === 0) {
       this.showPreviousMonth(() => this.focusLastDayOfMonth());
     } else {
@@ -311,7 +311,7 @@ export default class DayPicker extends Component {
   focusNextDay(dayNode) {
     const dayNodes = Helpers.getDayNodes(this.dayPicker, this.props.classNames);
     const dayNodeIndex = Helpers.nodeListToArray(dayNodes).indexOf(dayNode);
-
+    if (dayNodeIndex === -1) return;
     if (dayNodeIndex === dayNodes.length - 1) {
       this.showNextMonth(() => this.focusFirstDayOfMonth());
     } else {

From cf40a4cbc99cd7158b97b01fe24e6733aa7ca8b3 Mon Sep 17 00:00:00 2001
From: Giampaolo Bellavite <gpbellavite@gmail.com>
Date: Mon, 5 Mar 2018 09:42:11 +0100
Subject: [PATCH 2/2] Add unit tests for not found nodes

---
 test/daypicker/methods.js | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/test/daypicker/methods.js b/test/daypicker/methods.js
index ec55860ec4..90e706442e 100644
--- a/test/daypicker/methods.js
+++ b/test/daypicker/methods.js
@@ -258,6 +258,11 @@ describe('DayPicker’s methods', () => {
         expect(document.activeElement.innerHTML).toBe('31');
         expect(instance.state.currentMonth.getMonth()).toBe(4);
       });
+      it('should not throw an error when the node is not found', () => {
+        expect(() =>
+          instance.focusPreviousDay(document.createElement('div'))
+        ).not.toThrow();
+      });
     });
 
     describe('focusNextDay()', () => {
@@ -301,6 +306,11 @@ describe('DayPicker’s methods', () => {
         expect(document.activeElement.innerHTML).toBe('1');
         expect(instance.state.currentMonth.getMonth()).toBe(2);
       });
+      it('should not throw an error when the node is not found', () => {
+        expect(() =>
+          instance.focusNextDay(document.createElement('div'))
+        ).not.toThrow();
+      });
     });
 
     describe('focusNextWeek()', () => {