diff --git a/assets/js/app.js b/assets/js/app.js
index 5b1ebab6..a64ec696 100644
--- a/assets/js/app.js
+++ b/assets/js/app.js
@@ -5,14 +5,6 @@
 // the compiled file.
 //
 
-// Third-party code, polyfills
-import './vendor/promise.polyfill';
-import './vendor/fetch.polyfill';
-import './vendor/closest.polyfill';
-import './vendor/customevent.polyfill';
-import './vendor/es6.polyfill';
-import './vendor/values-entries.polyfill';
-
 // Our code
 import './ujs';
 import './when-ready';
diff --git a/assets/js/vendor/closest.polyfill.js b/assets/js/vendor/closest.polyfill.js
deleted file mode 100644
index 2c60a6d5..00000000
--- a/assets/js/vendor/closest.polyfill.js
+++ /dev/null
@@ -1,31 +0,0 @@
-// element-closest | CC0-1.0 | github.com/jonathantneal/closest
-
-if (typeof Element.prototype.matches !== 'function') {
-  Element.prototype.matches = Element.prototype.msMatchesSelector || Element.prototype.mozMatchesSelector || Element.prototype.webkitMatchesSelector || function matches(selector) {
-    var element = this;
-    var elements = (element.document || element.ownerDocument).querySelectorAll(selector);
-    var index = 0;
-
-    while (elements[index] && elements[index] !== element) {
-      ++index;
-    }
-
-    return Boolean(elements[index]);
-  };
-}
-
-if (typeof Element.prototype.closest !== 'function') {
-  Element.prototype.closest = function closest(selector) {
-    var element = this;
-
-    while (element && element.nodeType === 1) {
-      if (element.matches(selector)) {
-        return element;
-      }
-
-      element = element.parentNode;
-    }
-
-    return null;
-  };
-}
diff --git a/assets/js/vendor/customevent.polyfill.js b/assets/js/vendor/customevent.polyfill.js
deleted file mode 100644
index 7d13f9cf..00000000
--- a/assets/js/vendor/customevent.polyfill.js
+++ /dev/null
@@ -1,17 +0,0 @@
-// https://developer.mozilla.org/en-US/docs/Web/API/CustomEvent/CustomEvent
-
-(function () {
-
-  if ( typeof window.CustomEvent === "function" ) return false;
-
-  function CustomEvent ( event, params ) {
-    params = params || { bubbles: false, cancelable: false, detail: undefined };
-    var evt = document.createEvent( 'CustomEvent' );
-    evt.initCustomEvent( event, params.bubbles, params.cancelable, params.detail );
-    return evt;
-   }
-
-  CustomEvent.prototype = window.Event.prototype;
-
-  window.CustomEvent = CustomEvent;
-})();
diff --git a/assets/js/vendor/es6.polyfill.js b/assets/js/vendor/es6.polyfill.js
deleted file mode 100644
index 51c1c423..00000000
--- a/assets/js/vendor/es6.polyfill.js
+++ /dev/null
@@ -1,104 +0,0 @@
-/**
- * ES6 methods polyfill
- * Sourced from their respective articles on MDN
- */
-
-if (!Array.prototype.find) {
-  Array.prototype.find = function(predicate) {
-    'use strict';
-    if (this == null) {
-      throw new TypeError('Array.prototype.find called on null or undefined');
-    }
-    if (typeof predicate !== 'function') {
-      throw new TypeError('predicate must be a function');
-    }
-    var list = Object(this);
-    var length = list.length >>> 0;
-    var thisArg = arguments[1];
-    var value;
-
-    for (var i = 0; i < length; i++) {
-      value = list[i];
-      if (predicate.call(thisArg, value, i, list)) {
-        return value;
-      }
-    }
-    return undefined;
-  };
-}
-
-if (!Array.prototype.findIndex) {
-  Array.prototype.findIndex = function(predicate) {
-    'use strict';
-    if (this == null) {
-      throw new TypeError('Array.prototype.findIndex called on null or undefined');
-    }
-    if (typeof predicate !== 'function') {
-      throw new TypeError('predicate must be a function');
-    }
-    var list = Object(this);
-    var length = list.length >>> 0;
-    var thisArg = arguments[1];
-    var value;
-
-    for (var i = 0; i < length; i++) {
-      value = list[i];
-      if (predicate.call(thisArg, value, i, list)) {
-        return i;
-      }
-    }
-    return -1;
-  };
-}
-
-if (!Array.prototype.includes) {
-  Array.prototype.includes = function(searchElement /*, fromIndex*/) {
-    'use strict';
-    if (this == null) {
-      throw new TypeError('Array.prototype.includes called on null or undefined');
-    }
-
-    var O = Object(this);
-    var len = parseInt(O.length, 10) || 0;
-    if (len === 0) {
-      return false;
-    }
-    var n = parseInt(arguments[1], 10) || 0;
-    var k;
-    if (n >= 0) {
-      k = n;
-    } else {
-      k = len + n;
-      if (k < 0) {k = 0;}
-    }
-    var currentElement;
-    while (k < len) {
-      currentElement = O[k];
-      if (searchElement === currentElement ||
-         (searchElement !== searchElement && currentElement !== currentElement)) { // NaN !== NaN
-        return true;
-      }
-      k++;
-    }
-    return false;
-  };
-}
-
-if (!String.prototype.startsWith) {
-    String.prototype.startsWith = function(searchString, position){
-      position = position || 0;
-      return this.substr(position, searchString.length) === searchString;
-  };
-}
-
-if (!String.prototype.endsWith) {
-  String.prototype.endsWith = function(searchString, position) {
-      var subjectString = this.toString();
-      if (typeof position !== 'number' || !isFinite(position) || Math.floor(position) !== position || position > subjectString.length) {
-        position = subjectString.length;
-      }
-      position -= searchString.length;
-      var lastIndex = subjectString.lastIndexOf(searchString, position);
-      return lastIndex !== -1 && lastIndex === position;
-  };
-}
diff --git a/assets/js/vendor/fetch.polyfill.js b/assets/js/vendor/fetch.polyfill.js
deleted file mode 100644
index 456f8c1f..00000000
--- a/assets/js/vendor/fetch.polyfill.js
+++ /dev/null
@@ -1,53 +0,0 @@
-if (typeof window.fetch !== 'function') {
-  window.fetch = function fetch(url, options) {
-    return new Promise((resolve, reject) => {
-      let request = new XMLHttpRequest();
-
-      options = options || {};
-      request.open(options.method || 'GET', url);
-
-      for (const i in options.headers) {
-        request.setRequestHeader(i, options.headers[i]);
-      }
-
-      request.withCredentials = options.credentials === 'include' || options.credentials === 'same-origin';
-      request.onload = () => resolve(response());
-      request.onerror = reject;
-
-      // IE11 hack: don't send null/undefined
-      if (options.body != null)
-        request.send(options.body);
-      else
-        request.send();
-
-      function response() {
-        const keys = [], all = [], headers = {};
-        let header;
-
-        request.getAllResponseHeaders().replace(/^(.*?):\s*([\s\S]*?)$/gm, (m, key, value) => {
-          keys.push(key = key.toLowerCase());
-          all.push([key, value]);
-          header = headers[key];
-          headers[key] = header ? `${header},${value}` : value;
-        });
-
-        return {
-          ok: (request.status/200|0) === 1,
-          status: request.status,
-          statusText: request.statusText,
-          url: request.responseURL,
-          clone: response,
-          text: () => Promise.resolve(request.responseText),
-          json: () => Promise.resolve(request.responseText).then(JSON.parse),
-          blob: () => Promise.resolve(new Blob([request.response])),
-          headers: {
-            keys: () => keys,
-            entries: () => all,
-            get: n => headers[n.toLowerCase()],
-            has: n => n.toLowerCase() in headers
-          }
-        };
-      }
-    });
-  };
-}
diff --git a/assets/js/vendor/promise.polyfill.js b/assets/js/vendor/promise.polyfill.js
deleted file mode 100644
index e02758e3..00000000
--- a/assets/js/vendor/promise.polyfill.js
+++ /dev/null
@@ -1,225 +0,0 @@
-(function (root) {
-  if (root.Promise) return;
-
-  // Store setTimeout reference so promise-polyfill will be unaffected by
-  // other code modifying setTimeout (like sinon.useFakeTimers())
-  var setTimeoutFunc = setTimeout;
-
-  function noop() {
-  }
-
-  // Use polyfill for setImmediate for performance gains
-  function asap(fn) {
-    setTimeoutFunc(fn, 1);
-  }
-
-  var onUnhandledRejection = function onUnhandledRejection(err) {
-    console.warn('Possible Unhandled Promise Rejection:', err); // eslint-disable-line no-console
-  };
-
-  // Polyfill for Function.prototype.bind
-  function bind(fn, thisArg) {
-    return function () {
-      fn.apply(thisArg, arguments);
-    };
-  }
-
-  var isArray = Array.isArray || function (value) {
-    return Object.prototype.toString.call(value) === '[object Array]';
-  };
-
-  function Promise(fn) {
-    if (typeof this !== 'object') throw new TypeError('Promises must be constructed via new');
-    if (typeof fn !== 'function') throw new TypeError('not a function');
-    this._state = 0;
-    this._handled = false;
-    this._value = undefined;
-    this._deferreds = [];
-
-    doResolve(fn, this);
-  }
-
-  function handle(self, deferred) {
-    while (self._state === 3) {
-      self = self._value;
-    }
-    if (self._state === 0) {
-      self._deferreds.push(deferred);
-      return;
-    }
-    self._handled = true;
-    asap(function () {
-      var cb = self._state === 1 ? deferred.onFulfilled : deferred.onRejected;
-      if (cb === null) {
-        (self._state === 1 ? resolve : reject)(deferred.promise, self._value);
-        return;
-      }
-      var ret;
-      try {
-        ret = cb(self._value);
-      } catch (e) {
-        reject(deferred.promise, e);
-        return;
-      }
-      resolve(deferred.promise, ret);
-    });
-  }
-
-  function resolve(self, newValue) {
-    try {
-      // Promise Resolution Procedure: https://github.com/promises-aplus/promises-spec#the-promise-resolution-procedure
-      if (newValue === self) throw new TypeError('A promise cannot be resolved with itself.');
-      if (newValue && (typeof newValue === 'object' || typeof newValue === 'function')) {
-        var then = newValue.then;
-        if (newValue instanceof Promise) {
-          self._state = 3;
-          self._value = newValue;
-          finale(self);
-          return;
-        } else if (typeof then === 'function') {
-          doResolve(bind(then, newValue), self);
-          return;
-        }
-      }
-      self._state = 1;
-      self._value = newValue;
-      finale(self);
-    } catch (e) {
-      reject(self, e);
-    }
-  }
-
-  function reject(self, newValue) {
-    self._state = 2;
-    self._value = newValue;
-    finale(self);
-  }
-
-  function finale(self) {
-    if (self._state === 2 && self._deferreds.length === 0) {
-      setTimeout(function() {
-        if (!self._handled) {
-          onUnhandledRejection(self._value);
-        }
-      }, 1);
-    }
-
-    for (var i = 0, len = self._deferreds.length; i < len; i++) {
-      handle(self, self._deferreds[i]);
-    }
-    self._deferreds = null;
-  }
-
-  function Handler(onFulfilled, onRejected, promise) {
-    this.onFulfilled = typeof onFulfilled === 'function' ? onFulfilled : null;
-    this.onRejected = typeof onRejected === 'function' ? onRejected : null;
-    this.promise = promise;
-  }
-
-  /**
-   * Take a potentially misbehaving resolver function and make sure
-   * onFulfilled and onRejected are only called once.
-   *
-   * Makes no guarantees about asynchrony.
-   */
-  function doResolve(fn, self) {
-    var done = false;
-    try {
-      fn(function (value) {
-        if (done) return;
-        done = true;
-        resolve(self, value);
-      }, function (reason) {
-        if (done) return;
-        done = true;
-        reject(self, reason);
-      });
-    } catch (ex) {
-      if (done) return;
-      done = true;
-      reject(self, ex);
-    }
-  }
-
-  Promise.prototype['catch'] = function (onRejected) {
-    return this.then(null, onRejected);
-  };
-
-  Promise.prototype.then = function (onFulfilled, onRejected) {
-    var prom = new Promise(noop);
-    handle(this, new Handler(onFulfilled, onRejected, prom));
-    return prom;
-  };
-
-  Promise.all = function () {
-    var args = Array.prototype.slice.call(arguments.length === 1 && isArray(arguments[0]) ? arguments[0] : arguments);
-
-    return new Promise(function (resolve, reject) {
-      if (args.length === 0) return resolve([]);
-      var remaining = args.length;
-
-      function res(i, val) {
-        try {
-          if (val && (typeof val === 'object' || typeof val === 'function')) {
-            var then = val.then;
-            if (typeof then === 'function') {
-              then.call(val, function (val) {
-                res(i, val);
-              }, reject);
-              return;
-            }
-          }
-          args[i] = val;
-          if (--remaining === 0) {
-            resolve(args);
-          }
-        } catch (ex) {
-          reject(ex);
-        }
-      }
-
-      for (var i = 0; i < args.length; i++) {
-        res(i, args[i]);
-      }
-    });
-  };
-
-  Promise.resolve = function (value) {
-    if (value && typeof value === 'object' && value.constructor === Promise) {
-      return value;
-    }
-
-    return new Promise(function (resolve) {
-      resolve(value);
-    });
-  };
-
-  Promise.reject = function (value) {
-    return new Promise(function (resolve, reject) {
-      reject(value);
-    });
-  };
-
-  Promise.race = function (values) {
-    return new Promise(function (resolve, reject) {
-      for (var i = 0, len = values.length; i < len; i++) {
-        values[i].then(resolve, reject);
-      }
-    });
-  };
-
-  /**
-   * Set the immediate function to execute callbacks
-   * @param fn {function} Function to execute
-   * @private
-   */
-  Promise._setImmediateFn = function _setImmediateFn(fn) {
-    asap = fn;
-  };
-
-  Promise._setUnhandledRejectionFn = function _setUnhandledRejectionFn(fn) {
-    onUnhandledRejection = fn;
-  };
-
-  root.Promise = Promise;
-})(window);
diff --git a/assets/js/vendor/values-entries.polyfill.js b/assets/js/vendor/values-entries.polyfill.js
deleted file mode 100644
index c8896e2f..00000000
--- a/assets/js/vendor/values-entries.polyfill.js
+++ /dev/null
@@ -1,17 +0,0 @@
-// object-values | MIT | github.com/tc39/proposal-object-values-entries
-
-const reduce = Function.bind.call(Function.call, Array.prototype.reduce);
-const isEnumerable = Function.bind.call(Function.call, Object.prototype.propertyIsEnumerable);
-const concat = Function.bind.call(Function.call, Array.prototype.concat);
-
-if (!Object.values) {
-  Object.values = function values(O) {
-    return reduce(Object.keys(O), (v, k) => concat(v, typeof k === 'string' && isEnumerable(O, k) ? [O[k]] : []), []);
-  };
-}
-
-if (!Object.entries) {
-  Object.entries = function entries(O) {
-    return reduce(Object.keys(O), (e, k) => concat(e, typeof k === 'string' && isEnumerable(O, k) ? [[k, O[k]]] : []), []);
-  };
-}