Tailwind Build Error

tailwind.js

{
  ...
  plugins: [
    require('./resources/assets/js/plugins/transition')({
      default: 0.15,
      slow: 0.25,
    }),
  ]
}

transition.js

export default options => {
    return ({ rule, addUtilities }) => {
        let transitions = [];

        for (let name in options) {
            transitions.push(
                selector(name === 'default' ? '.transition' : `.transition-${name}`, {
                    'transition': `all ${options[name]}s ease`
                })
            );
        }

        addUtilities([
            ...transitions
        ]);
    }
}

webpack.mix.js

let mix = require('laravel-mix');
let tailwindcss = require('tailwindcss');

mix
    .js('resources/assets/js/app.js', 'public/js')
    .sass('resources/assets/sass/app.scss', 'public/css')
    .version()
    .options({
        processCssUrls: false,
        postCss: [tailwindcss('tailwind.js')]
    });