How to use the modernizr.classlist function in modernizr

// Get our browser up to date with polyfills.
const Modernizr = require('modernizr');
if (!Modernizr.classlist) {
  require('classlist-polyfill'); // DOM element classList support.
}
if (!Modernizr.dataset) {
  require('dataset');  // dataSet accessor support.
}

// This polyfill has its own test logic so no need to conditionally require.
require('polyfill-function-prototype-bind');

// Bring in foundation and custom libraries.
require('foundation/js/foundation/foundation');

// Detect if this is a child frame. If yes, initialize the react devtools hook to work around
//   https://github.com/facebook/react-devtools/issues/57
// This must occur before any react code is loaded.
if (window.parent !== window) {
  window.__REACT_DEVTOOLS_GLOBAL_HOOK__ = window.parent.__REACT_DEVTOOLS_GLOBAL_HOOK__;
}

require('../sass/style.scss');

// Get our browser up to date with polyfills.
// TODO(awong): These do NOT correctly conditionally load the polyfill.
// The polyfill is always loaded. require.ensure() should be used instead but
// then load ordering needs to be worked out. Fix later.
const Modernizr = require('modernizr');
if (!Modernizr.classlist) {
  require('classlist-polyfill'); // DOM element classList support.
}
if (!Modernizr.dataset) {
  require('dataset');  // dataSet accessor support.
}

// This polyfill has its own test logic so no need to conditionally require.
require('polyfill-function-prototype-bind');

// Bring in foundation and custom libraries.
require('foundation-sites');
require('./legacy/components.js');

// Only used in facility-locator index and some playbook examples.
require('jquery-accessible-simple-tooltip-aria/jquery-accessible-simple-tooltip-aria.js');
require('./legacy/menu.js');

// Add all the ES6 library features that my be missing.
require('babel-polyfill');

// Get our browser up to date with polyfills.
const Modernizr = require('modernizr');
if (!Modernizr.classlist) {
  require('classlist-polyfill'); // DOM element classList support.
}
if (!Modernizr.dataset) {
  require('dataset');  // dataSet accessor support.
}

// This polyfill has its own test logic so no need to conditionally require.
require('polyfill-function-prototype-bind');

// Bring in foundation and custom libraries.
require('foundation/js/foundation/foundation');
require('./components.js');

// Things that run on document.ready().
require('./vendor/jquery-accessible-simple-tooltip-aria.js'); // Only used in facility-locator index and some playbook examples.
require('./vendor/menu.js');