Node#isEmpty considers nbsp-only node as non-empty

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

Bug. (Or verification of intent).

What is the current behavior?

When a new block is created, it is padded with an   non-breaking space character. The behavior of Node#isEmpty disregards whitespace, but not specifically the non-breaking space character.

If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem via fiddle.tinymce.com or similar.

Demo: http://fiddle.tinymce.com/Pugaab

Enter some content and press Enter.

More directly, it could be reproduced by a test case on creating an empty text node.

const documentNode = Node.create( '#document-fragment' );
const textNode = Node.create( '#text' );
textNode.value = String.fromCharCode( 160 );
documentNode.append( textNode );
console.log( documentNode.isEmpty() );
// false

Possible solution: If changing the regular expression to use \s instead of , isEmpty correctly returns true.

Before:

https://github.com/tinymce/tinymce/blob/7dfd8102cadfb35e7304cacec7f122aa9e81b1ad/src/core/main/ts/api/html/Node.ts#L14

After:

const whiteSpaceRegExp = /^[\s\t\r\n]*$/;

What is the expected behavior?

The logged result should show "Is empty: true" since it is for the newly-created empty paragraph.

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

TinyMCE 4.7.13
Unaware of previous working state.