From 1a677469a96257426ed820f410f613df762917a5 Mon Sep 17 00:00:00 2001
From: George Kalpakas <kalpakas.g@gmail.com>
Date: Wed, 19 Sep 2018 11:06:19 +0300
Subject: [PATCH] fix(ngClass): do not break on invalid values

Previously, when an `ngClass` expression evaluated to something that was
not a string, array or object (and was truthy), an error would be thrown
while trying to call `.split()` on a non-string value. This error was
not very helpful for the user to identify the root cause of the problem.

This commit fixes it by ensuring such values are converted to string.

Fixes #16697
---
 src/ng/directive/ngClass.js      | 4 ++++
 test/ng/directive/ngClassSpec.js | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/src/ng/directive/ngClass.js b/src/ng/directive/ngClass.js
index 664e4810ce2..fc7b6db2c03 100644
--- a/src/ng/directive/ngClass.js
+++ b/src/ng/directive/ngClass.js
@@ -125,6 +125,8 @@ function classDirective(name, selector) {
   }
 
   function toClassString(classValue) {
+    if (!classValue) return classValue;
+
     var classString = classValue;
 
     if (isArray(classValue)) {
@@ -133,6 +135,8 @@ function classDirective(name, selector) {
       classString = Object.keys(classValue).
         filter(function(key) { return classValue[key]; }).
         join(' ');
+    } else if (!isString(classValue)) {
+      classString = classValue + '';
     }
 
     return classString;
diff --git a/test/ng/directive/ngClassSpec.js b/test/ng/directive/ngClassSpec.js
index 0180d67a6aa..74500505fd8 100644
--- a/test/ng/directive/ngClassSpec.js
+++ b/test/ng/directive/ngClassSpec.js
@@ -88,6 +88,12 @@ describe('ngClass', function() {
     expect(element.hasClass('AnotB')).toBeFalsy();
   }));
 
+  it('should not break when passed non-string/array/object, truthy values', inject(function($rootScope, $compile) {
+    element = $compile('<div ng-class="42"></div>')($rootScope);
+    $rootScope.$digest();
+    expect(element.hasClass('42')).toBeTruthy();
+  }));
+
   it('should support adding multiple classes via an array mixed with conditionally via a map', inject(function($rootScope, $compile) {
     element = $compile('<div class="existing" ng-class="[\'A\', {\'B\': condition}]"></div>')($rootScope);
     $rootScope.$digest();