Purifycss not deleting unused css class

Question

I have this code trying to delete the class hello3:

var purify = require('purify-css');
    var content = '<div class="hello"></div><div class="hello2"></div>';
    var css = '.hello { color: green; } .hello3 { display: block; }';

    var options = {
      output: 'purified.css',

      // Will minify CSS code in addition to purify.
      minify: true,

      // Logs out removed selectors.
      rejected: true
    };

    purify(content, css, options);

The output in purified.css is the same as the variable css:

.hello { color: green; } .hello3 { display: block; }

How to solve it?

Answer 1

I ran a test and confirmed that purify-css doesn't like class names that contain numbers.

My command... purifycss css/main.css page1.html --out css/purified.css --info --rejected took my main.css file and incompletely purified it into:

.page1-h1 {
  color: red;
}
.page2-h1 {
  color: blue;
}

This included an unused class (.page2-h1). But when I renamed my class names so that there were no number characters in it and then ran the same command again got the main.css that I expected which contained only:

.pageone-hone {
  color: red;
}

This seems to be a known problem too.