`noopener` seems didn't work

[uiolee]

noopener seems didn't work. i'am not sure.

hexo generate result:

<a target="_blank" href="http://hexo.io/" rel="external nofollow noreferrer">blank ahead</a>
<a href="http://hexo.io/" rel="external nofollow noreferrer" target="_blank">blank follow</a>
<a href="http://hexo.io/" rel="external nofollow noreferrer">no blank</a>

[uiolee]

Reproduce

1. hexo init test; cd test
2. hexo g, and get html of the post 'Hello World'
3. npm i hexo-filter-nofollow
4. hexo clean; hexo g, and get html of the post 'Hello World'
5. compare the result of steps 2 and 4

some links had noopener, but some don't.

result