DefinitelyTyped/types/postcss-nested/postcss-nested-tests.ts

import * as postcss from 'postcss';
import nested = require('postcss-nested');

const withDefaultOptions: postcss.Transformer = nested();
const withCustomOptions: postcss.Transformer = nested({
    bubble: ['phone'],
    unwrap: ['phone'],
    preserveEmpty: true
});

postcss().use(withDefaultOptions);
postcss().use(withCustomOptions);