(function (global, factory) {
	typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
	typeof define === 'function' && define.amd ? define('GOVUKFrontend.NotificationBanner', factory) :
	(global.GOVUKFrontend = global.GOVUKFrontend || {}, global.GOVUKFrontend.NotificationBanner = factory());
}(this, (function () { 'use strict';

(function(undefined) {

// Detection from https://github.com/Financial-Times/polyfill-service/blob/master/packages/polyfill-library/polyfills/Window/detect.js
var detect = ('Window' in this);

if (detect) return

// Polyfill from https://cdn.polyfill.io/v2/polyfill.js?features=Window&flags=always
if ((typeof WorkerGlobalScope === "undefined") && (typeof importScripts !== "function")) {
	(function (global) {
		if (global.constructor) {
			global.Window = global.constructor;
		} else {
			(global.Window = global.constructor = new Function('return function Window() {}')()).prototype = this;
		}
	}(this));
}

})
.call('object' === typeof window && window || 'object' === typeof self && self || 'object' === typeof global && global || {});

(function(undefined) {

// Detection from https://github.com/Financial-Times/polyfill-service/blob/master/packages/polyfill-library/polyfills/Document/detect.js
var detect = ("Document" in this);

if (detect) return

// Polyfill from https://cdn.polyfill.io/v2/polyfill.js?features=Document&flags=always
if ((typeof WorkerGlobalScope === "undefined") && (typeof importScripts !== "function")) {

	if (this.HTMLDocument) { // IE8

		// HTMLDocument is an extension of Document.  If the browser has HTMLDocument but not Document, the former will suffice as an alias for the latter.
		this.Document = this.HTMLDocument;

	} else {

		// Create an empty function to act as the missing constructor for the document object, attach the document object as its prototype.  The function needs to be anonymous else it is hoisted and causes the feature detect to prematurely pass, preventing the assignments below being made.
		this.Document = this.HTMLDocument = document.constructor = (new Function('return function Document() {}')());
		this.Document.prototype = document;
	}
}


})
.call('object' === typeof window && window || 'object' === typeof self && self || 'object' === typeof global && global || {});

(function(undefined) {

// Detection from https://github.com/Financial-Times/polyfill-service/blob/master/packages/polyfill-library/polyfills/Element/detect.js
var detect = ('Element' in this && 'HTMLElement' in this);

if (detect) return

// Polyfill from https://cdn.polyfill.io/v2/polyfill.js?features=Element&flags=always
(function () {

	// IE8
	if (window.Element && !window.HTMLElement) {
		window.HTMLElement = window.Element;
		return;
	}

	// create Element constructor
	window.Element = window.HTMLElement = new Function('return function Element() {}')();

	// generate sandboxed iframe
	var vbody = document.appendChild(document.createElement('body'));
	var frame = vbody.appendChild(document.createElement('iframe'));

	// use sandboxed iframe to replicate Element functionality
	var frameDocument = frame.contentWindow.document;
	var prototype = Element.prototype = frameDocument.appendChild(frameDocument.createElement('*'));
	var cache = {};

	// polyfill Element.prototype on an element
	var shiv = function (element, deep) {
		var
		childNodes = element.childNodes || [],
		index = -1,
		key, value, childNode;

		if (element.nodeType === 1 && element.constructor !== Element) {
			element.constructor = Element;

			for (key in cache) {
				value = cache[key];
				element[key] = value;
			}
		}

		while (childNode = deep && childNodes[++index]) {
			shiv(childNode, deep);
		}

		return element;
	};

	var elements = document.getElementsByTagName('*');
	var nativeCreateElement = document.createElement;
	var interval;
	var loopLimit = 100;

	prototype.attachEvent('onpropertychange', function (event) {
		var
		propertyName = event.propertyName,
		nonValue = !cache.hasOwnProperty(propertyName),
		newValue = prototype[propertyName],
		oldValue = cache[propertyName],
		index = -1,
		element;

		while (element = elements[++index]) {
			if (element.nodeType === 1) {
				if (nonValue || element[propertyName] === oldValue) {
					element[propertyName] = newValue;
				}
			}
		}

		cache[propertyName] = newValue;
	});

	prototype.constructor = Element;

	if (!prototype.hasAttribute) {
		// <Element>.hasAttribute
		prototype.hasAttribute = function hasAttribute(name) {
			return this.getAttribute(name) !== null;
		};
	}

	// Apply Element prototype to the pre-existing DOM as soon as the body element appears.
	function bodyCheck() {
		if (!(loopLimit--)) clearTimeout(interval);
		if (document.body && !document.body.prototype && /(complete|interactive)/.test(document.readyState)) {
			shiv(document, true);
			if (interval && document.body.prototype) clearTimeout(interval);
			return (!!document.body.prototype);
		}
		return false;
	}
	if (!bodyCheck()) {
		document.onreadystatechange = bodyCheck;
		interval = setInterval(bodyCheck, 25);
	}

	// Apply to any new elements created after load
	document.createElement = function createElement(nodeName) {
		var element = nativeCreateElement(String(nodeName).toLowerCase());
		return shiv(element);
	};

	// remove sandboxed iframe
	document.removeChild(vbody);
}());

})
.call('object' === typeof window && window || 'object' === typeof self && self || 'object' === typeof global && global || {});

(function(undefined) {

// Detection from https://github.com/Financial-Times/polyfill-service/blob/master/packages/polyfill-library/polyfills/Object/defineProperty/detect.js
var detect = (
  // In IE8, defineProperty could only act on DOM elements, so full support
  // for the feature requires the ability to set a property on an arbitrary object
  'defineProperty' in Object && (function() {
  	try {
  		var a = {};
  		Object.defineProperty(a, 'test', {value:42});
  		return true;
  	} catch(e) {
  		return false
  	}
  }())
);

if (detect) return

// Polyfill from https://cdn.polyfill.io/v2/polyfill.js?features=Object.defineProperty&flags=always
(function (nativeDefineProperty) {

	var supportsAccessors = Object.prototype.hasOwnProperty('__defineGetter__');
	var ERR_ACCESSORS_NOT_SUPPORTED = 'Getters & setters cannot be defined on this javascript engine';
	var ERR_VALUE_ACCESSORS = 'A property cannot both have accessors and be writable or have a value';

	Object.defineProperty = function defineProperty(object, property, descriptor) {

		// Where native support exists, assume it
		if (nativeDefineProperty && (object === window || object === document || object === Element.prototype || object instanceof Element)) {
			return nativeDefineProperty(object, property, descriptor);
		}

		if (object === null || !(object instanceof Object || typeof object === 'object')) {
			throw new TypeError('Object.defineProperty called on non-object');
		}

		if (!(descriptor instanceof Object)) {
			throw new TypeError('Property description must be an object');
		}

		var propertyString = String(property);
		var hasValueOrWritable = 'value' in descriptor || 'writable' in descriptor;
		var getterType = 'get' in descriptor && typeof descriptor.get;
		var setterType = 'set' in descriptor && typeof descriptor.set;

		// handle descriptor.get
		if (getterType) {
			if (getterType !== 'function') {
				throw new TypeError('Getter must be a function');
			}
			if (!supportsAccessors) {
				throw new TypeError(ERR_ACCESSORS_NOT_SUPPORTED);
			}
			if (hasValueOrWritable) {
				throw new TypeError(ERR_VALUE_ACCESSORS);
			}
			Object.__defineGetter__.call(object, propertyString, descriptor.get);
		} else {
			object[propertyString] = descriptor.value;
		}

		// handle descriptor.set
		if (setterType) {
			if (setterType !== 'function') {
				throw new TypeError('Setter must be a function');
			}
			if (!supportsAccessors) {
				throw new TypeError(ERR_ACCESSORS_NOT_SUPPORTED);
			}
			if (hasValueOrWritable) {
				throw new TypeError(ERR_VALUE_ACCESSORS);
			}
			Object.__defineSetter__.call(object, propertyString, descriptor.set);
		}

		// OK to define value unconditionally - if a getter has been specified as well, an error would be thrown above
		if ('value' in descriptor) {
			object[propertyString] = descriptor.value;
		}

		return object;
	};
}(Object.defineProperty));
})
.call('object' === typeof window && window || 'object' === typeof self && self || 'object' === typeof global && global || {});

(function(undefined) {

// Detection from https://github.com/Financial-Times/polyfill-service/blob/master/packages/polyfill-library/polyfills/Event/detect.js
var detect = (
  (function(global) {

  	if (!('Event' in global)) return false;
  	if (typeof global.Event === 'function') return true;

  	try {

  		// In IE 9-11, the Event object exists but cannot be instantiated
  		new Event('click');
  		return true;
  	} catch(e) {
  		return false;
  	}
  }(this))
);

if (detect) return

// Polyfill from https://cdn.polyfill.io/v2/polyfill.js?features=Event&flags=always
(function () {
	var unlistenableWindowEvents = {
		click: 1,
		dblclick: 1,
		keyup: 1,
		keypress: 1,
		keydown: 1,
		mousedown: 1,
		mouseup: 1,
		mousemove: 1,
		mouseover: 1,
		mouseenter: 1,
		mouseleave: 1,
		mouseout: 1,
		storage: 1,
		storagecommit: 1,
		textinput: 1
	};

	// This polyfill depends on availability of `document` so will not run in a worker
	// However, we asssume there are no browsers with worker support that lack proper
	// support for `Event` within the worker
	if (typeof document === 'undefined' || typeof window === 'undefined') return;

	function indexOf(array, element) {
		var
		index = -1,
		length = array.length;

		while (++index < length) {
			if (index in array && array[index] === element) {
				return index;
			}
		}

		return -1;
	}

	var existingProto = (window.Event && window.Event.prototype) || null;
	window.Event = Window.prototype.Event = function Event(type, eventInitDict) {
		if (!type) {
			throw new Error('Not enough arguments');
		}

		var event;
		// Shortcut if browser supports createEvent
		if ('createEvent' in document) {
			event = document.createEvent('Event');
			var bubbles = eventInitDict && eventInitDict.bubbles !== undefined ? eventInitDict.bubbles : false;
			var cancelable = eventInitDict && eventInitDict.cancelable !== undefined ? eventInitDict.cancelable : false;

			event.initEvent(type, bubbles, cancelable);

			return event;
		}

		event = document.createEventObject();

		event.type = type;
		event.bubbles = eventInitDict && eventInitDict.bubbles !== undefined ? eventInitDict.bubbles : false;
		event.cancelable = eventInitDict && eventInitDict.cancelable !== undefined ? eventInitDict.cancelable : false;

		return event;
	};
	if (existingProto) {
		Object.defineProperty(window.Event, 'prototype', {
			configurable: false,
			enumerable: false,
			writable: true,
			value: existingProto
		});
	}

	if (!('createEvent' in document)) {
		window.addEventListener = Window.prototype.addEventListener = Document.prototype.addEventListener = Element.prototype.addEventListener = function addEventListener() {
			var
			element = this,
			type = arguments[0],
			listener = arguments[1];

			if (element === window && type in unlistenableWindowEvents) {
				throw new Error('In IE8 the event: ' + type + ' is not available on the window object. Please see https://github.com/Financial-Times/polyfill-service/issues/317 for more information.');
			}

			if (!element._events) {
				element._events = {};
			}

			if (!element._events[type]) {
				element._events[type] = function (event) {
					var
					list = element._events[event.type].list,
					events = list.slice(),
					index = -1,
					length = events.length,
					eventElement;

					event.preventDefault = function preventDefault() {
						if (event.cancelable !== false) {
							event.returnValue = false;
						}
					};

					event.stopPropagation = function stopPropagation() {
						event.cancelBubble = true;
					};

					event.stopImmediatePropagation = function stopImmediatePropagation() {
						event.cancelBubble = true;
						event.cancelImmediate = true;
					};

					event.currentTarget = element;
					event.relatedTarget = event.fromElement || null;
					event.target = event.target || event.srcElement || element;
					event.timeStamp = new Date().getTime();

					if (event.clientX) {
						event.pageX = event.clientX + document.documentElement.scrollLeft;
						event.pageY = event.clientY + document.documentElement.scrollTop;
					}

					while (++index < length && !event.cancelImmediate) {
						if (index in events) {
							eventElement = events[index];

							if (indexOf(list, eventElement) !== -1 && typeof eventElement === 'function') {
								eventElement.call(element, event);
							}
						}
					}
				};

				element._events[type].list = [];

				if (element.attachEvent) {
					element.attachEvent('on' + type, element._events[type]);
				}
			}

			element._events[type].list.push(listener);
		};

		window.removeEventListener = Window.prototype.removeEventListener = Document.prototype.removeEventListener = Element.prototype.removeEventListener = function removeEventListener() {
			var
			element = this,
			type = arguments[0],
			listener = arguments[1],
			index;

			if (element._events && element._events[type] && element._events[type].list) {
				index = indexOf(element._events[type].list, listener);

				if (index !== -1) {
					element._events[type].list.splice(index, 1);

					if (!element._events[type].list.length) {
						if (element.detachEvent) {
							element.detachEvent('on' + type, element._events[type]);
						}
						delete element._events[type];
					}
				}
			}
		};

		window.dispatchEvent = Window.prototype.dispatchEvent = Document.prototype.dispatchEvent = Element.prototype.dispatchEvent = function dispatchEvent(event) {
			if (!arguments.length) {
				throw new Error('Not enough arguments');
			}

			if (!event || typeof event.type !== 'string') {
				throw new Error('DOM Events Exception 0');
			}

			var element = this, type = event.type;

			try {
				if (!event.bubbles) {
					event.cancelBubble = true;

					var cancelBubbleEvent = function (event) {
						event.cancelBubble = true;

						(element || window).detachEvent('on' + type, cancelBubbleEvent);
					};

					this.attachEvent('on' + type, cancelBubbleEvent);
				}

				this.fireEvent('on' + type, event);
			} catch (error) {
				event.target = element;

				do {
					event.currentTarget = element;

					if ('_events' in element && typeof element._events[type] === 'function') {
						element._events[type].call(element, event);
					}

					if (typeof element['on' + type] === 'function') {
						element['on' + type].call(element, event);
					}

					element = element.nodeType === 9 ? element.parentWindow : element.parentNode;
				} while (element && !event.cancelBubble);
			}

			return true;
		};

		// Add the DOMContentLoaded Event
		document.attachEvent('onreadystatechange', function() {
			if (document.readyState === 'complete') {
				document.dispatchEvent(new Event('DOMContentLoaded', {
					bubbles: true
				}));
			}
		});
	}
}());

})
.call('object' === typeof window && window || 'object' === typeof self && self || 'object' === typeof global && global || {});

/**
 * Common helpers which do not require polyfill.
 *
 * IMPORTANT: If a helper require a polyfill, please isolate it in its own module
 * so that the polyfill can be properly tree-shaken and does not burden
 * the components that do not need that helper
 *
 * @module common/index
 */

/**
 * Config flattening function
 *
 * Takes any number of objects, flattens them into namespaced key-value pairs,
 * (e.g. {'i18n.showSection': 'Show section'}) and combines them together, with
 * greatest priority on the LAST item passed in.
 *
 * @returns {object} A flattened object of key-value pairs.
 */
function mergeConfigs (/* configObject1, configObject2, ...configObjects */) {
  /**
   * Function to take nested objects and flatten them to a dot-separated keyed
   * object. Doing this means we don't need to do any deep/recursive merging of
   * each of our objects, nor transform our dataset from a flat list into a
   * nested object.
   *
   * @param {object} configObject - Deeply nested object
   * @returns {object} Flattened object with dot-separated keys
   */
  var flattenObject = function (configObject) {
    // Prepare an empty return object
    var flattenedObject = {};

    // Our flattening function, this is called recursively for each level of
    // depth in the object. At each level we prepend the previous level names to
    // the key using `prefix`.
    var flattenLoop = function (obj, prefix) {
      // Loop through keys...
      for (var key in obj) {
        // Check to see if this is a prototypical key/value,
        // if it is, skip it.
        if (!Object.prototype.hasOwnProperty.call(obj, key)) {
          continue
        }
        var value = obj[key];
        var prefixedKey = prefix ? prefix + '.' + key : key;
        if (typeof value === 'object') {
          // If the value is a nested object, recurse over that too
          flattenLoop(value, prefixedKey);
        } else {
          // Otherwise, add this value to our return object
          flattenedObject[prefixedKey] = value;
        }
      }
    };

    // Kick off the recursive loop
    flattenLoop(configObject);
    return flattenedObject
  };

  // Start with an empty object as our base
  var formattedConfigObject = {};

  // Loop through each of the remaining passed objects and push their keys
  // one-by-one into configObject. Any duplicate keys will override the existing
  // key with the new value.
  for (var i = 0; i < arguments.length; i++) {
    var obj = flattenObject(arguments[i]);
    for (var key in obj) {
      if (Object.prototype.hasOwnProperty.call(obj, key)) {
        formattedConfigObject[key] = obj[key];
      }
    }
  }

  return formattedConfigObject
}

/**
 * @callback nodeListIterator
 * @param {Element} value - The current node being iterated on
 * @param {number} index - The current index in the iteration
 * @param {NodeListOf<Element>} nodes - NodeList from querySelectorAll()
 * @returns {undefined}
 */

(function(undefined) {

  // Detection from https://raw.githubusercontent.com/Financial-Times/polyfill-library/13cf7c340974d128d557580b5e2dafcd1b1192d1/polyfills/Element/prototype/dataset/detect.js
  var detect = (function(){
    if (!document.documentElement.dataset) {
      return false;
    }
    var el = document.createElement('div');
    el.setAttribute("data-a-b", "c");
    return el.dataset && el.dataset.aB == "c";
  }());

  if (detect) return

  // Polyfill derived from  https://raw.githubusercontent.com/Financial-Times/polyfill-library/13cf7c340974d128d557580b5e2dafcd1b1192d1/polyfills/Element/prototype/dataset/polyfill.js
  Object.defineProperty(Element.prototype, 'dataset', {
    get: function() {
      var element = this;
      var attributes = this.attributes;
      var map = {};
  
      for (var i = 0; i < attributes.length; i++) {
        var attribute = attributes[i];
  
        // This regex has been edited from the original polyfill, to add
        // support for period (.) separators in data-* attribute names. These
        // are allowed in the HTML spec, but were not covered by the original
        // polyfill's regex. We use periods in our i18n implementation.
        if (attribute && attribute.name && (/^data-\w[.\w-]*$/).test(attribute.name)) {
          var name = attribute.name;
          var value = attribute.value;
  
          var propName = name.substr(5).replace(/-./g, function (prop) {
            return prop.charAt(1).toUpperCase();
          });
          
          // If this browser supports __defineGetter__ and __defineSetter__,
          // continue using defineProperty. If not (like IE 8 and below), we use
          // a hacky fallback which at least gives an object in the right format
          if ('__defineGetter__' in Object.prototype && '__defineSetter__' in Object.prototype) {
            Object.defineProperty(map, propName, {
              enumerable: true,
              get: function() {
                return this.value;
              }.bind({value: value || ''}),
              set: function setter(name, value) {
                if (typeof value !== 'undefined') {
                  this.setAttribute(name, value);
                } else {
                  this.removeAttribute(name);
                }
              }.bind(element, name)
            });
          } else {
            map[propName] = value;
          }

        }
      }
  
      return map;
    }
  });

}).call('object' === typeof window && window || 'object' === typeof self && self || 'object' === typeof global && global || {});

(function(undefined) {

    // Detection from https://github.com/mdn/content/blob/cf607d68522cd35ee7670782d3ee3a361eaef2e4/files/en-us/web/javascript/reference/global_objects/string/trim/index.md#polyfill
    var detect = ('trim' in String.prototype);
    
    if (detect) return

    // Polyfill from https://github.com/mdn/content/blob/cf607d68522cd35ee7670782d3ee3a361eaef2e4/files/en-us/web/javascript/reference/global_objects/string/trim/index.md#polyfill
    String.prototype.trim = function () {
        return this.replace(/^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g, '');
    };

}).call('object' === typeof window && window || 'object' === typeof self && self || 'object' === typeof global && global || {});

/**
 * Normalise string
 *
 * 'If it looks like a duck, and it quacks like a duck…' 🦆
 *
 * If the passed value looks like a boolean or a number, convert it to a boolean
 * or number.
 *
 * Designed to be used to convert config passed via data attributes (which are
 * always strings) into something sensible.
 *
 * @param {string} value - The value to normalise
 * @returns {string | boolean | number | undefined} Normalised data
 */
function normaliseString (value) {
  if (typeof value !== 'string') {
    return value
  }

  var trimmedValue = value.trim();

  if (trimmedValue === 'true') {
    return true
  }

  if (trimmedValue === 'false') {
    return false
  }

  // Empty / whitespace-only strings are considered finite so we need to check
  // the length of the trimmed string as well
  if (trimmedValue.length > 0 && isFinite(trimmedValue)) {
    return Number(trimmedValue)
  }

  return value
}

/**
 * Normalise dataset
 *
 * Loop over an object and normalise each value using normaliseData function
 *
 * @param {DOMStringMap} dataset - HTML element dataset
 * @returns {Object<string, string | boolean | number | undefined>} Normalised dataset
 */
function normaliseDataset (dataset) {
  var out = {};

  for (var key in dataset) {
    out[key] = normaliseString(dataset[key]);
  }

  return out
}

/**
 * Notification Banner component
 *
 * @class
 * @param {HTMLElement} $module - HTML element to use for notification banner
 * @param {NotificationBannerConfig} config - Notification banner config
 */
function NotificationBanner ($module, config) {
  this.$module = $module;

  var defaultConfig = {
    disableAutoFocus: false
  };
  this.config = mergeConfigs(
    defaultConfig,
    config || {},
    normaliseDataset($module.dataset)
  );
}

/**
 * Initialise the component
 */
NotificationBanner.prototype.init = function () {
  var $module = this.$module;
  // Check for module
  if (!$module) {
    return
  }

  this.setFocus();
};

/**
 * Focus the element
 *
 * If `role="alert"` is set, focus the element to help some assistive technologies
 * prioritise announcing it.
 *
 * You can turn off the auto-focus functionality by setting `data-disable-auto-focus="true"` in the
 * component HTML. You might wish to do this based on user research findings, or to avoid a clash
 * with another element which should be focused when the page loads.
 */
NotificationBanner.prototype.setFocus = function () {
  var $module = this.$module;

  if (this.config.disableAutoFocus) {
    return
  }

  if ($module.getAttribute('role') !== 'alert') {
    return
  }

  // Set tabindex to -1 to make the element focusable with JavaScript.
  // Remove the tabindex on blur as the component doesn't need to be focusable after the page has
  // loaded.
  if (!$module.getAttribute('tabindex')) {
    $module.setAttribute('tabindex', '-1');

    $module.addEventListener('blur', function () {
      $module.removeAttribute('tabindex');
    });
  }

  $module.focus();
};

/**
 * Notification banner config
 *
 * @typedef {object} NotificationBannerConfig
 * @property {boolean} [disableAutoFocus = false] -
 *   If set to `true` the notification banner will not be focussed when the page
 *   loads. This only applies if the component has a `role` of `alert` – in
 *   other cases the component will not be focused on page load, regardless of
 *   this option.
 */

return NotificationBanner;

})));