Not able to configure purgecss in Mix

I've following folder structure:

https://www.dropbox.com/s/mxogeirt3fyulr9/Screenshot%202020-05-28%2021.27.02.png?dl=0

Vue files are under resources/assets/js/... SCSS files are under resources/assets/sass/...

My webpack.mix.js

const mix = require('laravel-mix');
require('laravel-mix-purgecss');

// ...
mix.js('resources/assets/js/app.js', 'public/js')
    .sass('resources/assets/sass/app.scss', 'public/css')
    .copy('resources/assets/images', 'public/images')
    .extract()
    .purgeCss({
        content: ['resources/assets/js/*.vue', 'resources/assets/js/**/*.vue'],
        extensions: ['mustache','html','js','hbs', 'vue', 'scss'],
        extractorPattern: [/[a-zA-Z0-9-:_/]+/g],
    })
    .browserSync('http://localhost:8080');

Please let me know what am I missing!