Use double quote when string literals are directly assigned to props.

cainakleao · cainakleao · commit 05a1c5ff1c41 · 2018-07-04T11:54:29.000+01:00
diff --git a/dev-server/src/index.js b/dev-server/src/index.js
@@ -50,7 +50,7 @@ ReactDom.render(
                 }
                 return false
             }}
-            defaultValue=''
+            defaultValue=""
         />
 
         <br />
