className doesn't work with is attribute is present

[yordis]

Do you want to request a feature or report a bug?

Report a bug

What is the current behavior?

When I pass is attribute the className don't work. It's output classname instead of class in the DOM.

**If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem.

Demo: https://jsfiddle.net/69z2wepo/63313/

What is the expected behavior?

Should render class instead of classname

Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?

"classnames": "^2.2.5",
"react": "^15.4.1",
"react-dom": "^15.4.1"

[gaearon]

is is a special DOM attribute opting you into using web components.
That documentation page mentions the issue:

One common confusion is that Web Components use "class" instead of "className".

The issue is discussed in detail in #4933 so I will refer you to that discussion.
I hope this helps!