The Patterns include a polyfill bundle [**dist/scripts/polyfill.js**](https://github.com/CityOfNewYork/ACCESS-NYC-PATTERNS/blob/master/src/js/polyfills.js) using [MDN Matches](https://developer.mozilla.org/en-US/docs/Web/API/Element/matches#Polyfill), [MDN Remove](https://developer.mozilla.org/en-US/docs/Web/API/ChildNode/remove#Polyfill), [whatwg-fetch](https://www.npmjs.com/package/whatwg-fetch) and features from the [Core JS Standard Libary](https://github.com/zloirock/core-js) (a dependency of [@babel/preset-env](https://babeljs.io/docs/en/babel-preset-env)). However, because this bundle includes all required polyfills so it is recommended to build your own polyfill based on your browser coverage requirements.