How to use cssnano-preset-default - 3 common examples

function resolvePreset(preset) {
    let fn, options;
    if (Array.isArray(preset)) {
        fn = preset[0];
        options = preset[1];
    } else {
        fn = preset;
        options = {};
    }
    // For JS setups where we invoked the preset already
    if (preset.plugins) {
        return Promise.resolve(preset.plugins);
    }
    // Provide an alias for the default preset, as it is built-in.
    if (fn === 'default') {
        return Promise.resolve(require('cssnano-preset-default')(options).plugins);
    }
    // For non-JS setups; we'll need to invoke the preset ourselves.
    if (typeof fn === 'function') {
        return Promise.resolve(fn(options).plugins);
    }
    // Try loading a preset from node_modules
    if ((0, _isResolvable2.default)(fn)) {
        return Promise.resolve(require(fn)(options).plugins);
    }
    const sugar = `cssnano-preset-${fn}`;
    // Try loading a preset from node_modules (sugar)
    if ((0, _isResolvable2.default)(sugar)) {
        return Promise.resolve(require(sugar)(options).plugins);
    }
    // If all else fails, we probably have a typo in the config somewhere
    throw new Error(`Cannot load preset "${fn}". Please check your configuration for errors and try again.`);

function resolvePreset(preset) {
    let fn, options;
    if (Array.isArray(preset)) {
        fn = preset[0];
        options = preset[1];
    } else {
        fn = preset;
        options = {};
    }
    // For JS setups where we invoked the preset already
    if (preset.plugins) {
        return Promise.resolve(preset.plugins);
    }
    // Provide an alias for the default preset, as it is built-in.
    if (fn === 'default') {
        return Promise.resolve(require('cssnano-preset-default')(options).plugins);
    }
    // For non-JS setups; we'll need to invoke the preset ourselves.
    if (typeof fn === 'function') {
        return Promise.resolve(fn(options).plugins);
    }
    // Try loading a preset from node_modules
    if ((0, _isResolvable2.default)(fn)) {
        return Promise.resolve(require(fn)(options).plugins);
    }
    const sugar = `cssnano-preset-${fn}`;
    // Try loading a preset from node_modules (sugar)
    if ((0, _isResolvable2.default)(sugar)) {
        return Promise.resolve(require(sugar)(options).plugins);
    }
    // If all else fails, we probably have a typo in the config somewhere
    throw new Error(`Cannot load preset "${fn}". Please check your configuration for errors and try again.`);

[require('postcss-bidirection'), {
    buildSelector: function (selector, direction) {
      return `[dir="${direction}"] ${selector}`
    }
  }],
  [require('autoprefixer'), { overrideBrowserslist: loadConfig('browserslist', require('@instructure/browserslist-config-instui')) }],
  [require('postcss-initial')],
  [require('postcss-reporter'), { clearReportedMessages: true }]
]

// For production builds we need to minify css with postcss here, we can't rely on babel/uglify to
// minify the css part of our js bundles because by the time they see it is just a string.
if ((process.env.BABEL_ENV || process.env.NODE_ENV) === 'production') {
  // we can't just use all of cssnano because there are some things it does that won't work for us,
  // so we filter them out.
  const minificationPlugins = require('cssnano-preset-default')({
    svgo: {'doesn\'t work': true}, // only has an async api and the css modules require hook needs everything to have a sync api
    convertValues: {'doesn\'t work': true}, // needs postcss 7+, when css-modules-require-hook uses 7.x, it should work
    mergeLonghand: {'doesn\'t work': true} // needs postcss 7+, when css-modules-require-hook uses 7.x, it should work
  }).plugins.filter(([_, pluginOpts = {}]) => !pluginOpts['doesn\'t work'])

  CORE_PLUGINS_POST.push(...minificationPlugins)
}

module.exports = function (opts = { before: {}, after: {}, nesting: false }) {
  return function (ctx = {}) {
    let plugins = [
      ...CORE_PLUGINS_PRE,
      opts.nesting ? [require('postcss-nesting')] : [require('postcss-nested')],
      ...CORE_PLUGINS_POST
    ]