Check that there is a prefix before trying to read the first character (fixes issues when testing with jsdom, clauderic#29)

Clauderic Demers · Clauderic Demers · commit 4830b84e2493 · 2016-06-25T10:19:15.000-04:00
diff --git a/src/utils.js b/src/utils.js
@@ -27,7 +27,7 @@ export const vendorPrefix = (function () {
         case 'ms':
             return 'ms';
         default:
-            return pre[0].toUpperCase() + pre.substr(1);
+            return (pre && pre.length) ? pre[0].toUpperCase() + pre.substr(1) : '';
     }
 })();
 

Original file line number	Diff line number	Diff line change
`@@ -27,7 +27,7 @@ export const vendorPrefix = (function () {`
`27`	`27`	`case 'ms':`
`28`	`28`	`return 'ms';`
`29`	`29`	`default:`
`30`		`- return pre[0].toUpperCase() + pre.substr(1);`
	`30`	`+ return (pre && pre.length) ? pre[0].toUpperCase() + pre.substr(1) : '';`
`31`	`31`	`}`
`32`	`32`	`})();`
`33`	`33`