export const canUseDOM = !!(
  typeof window !== 'undefined' &&
  window.document &&
  window.document.createElement
);

export function getConfirmation(message, callback) {
  callback(window.confirm(message)); // eslint-disable-line no-alert
}

/**
 * Returns true if the HTML5 history API is supported. Taken from Modernizr.
 *
 * https://github.com/Modernizr/Modernizr/blob/master/LICENSE
 * https://github.com/Modernizr/Modernizr/blob/master/feature-detects/history.js
 * changed to avoid false negatives for Windows Phones: https://github.com/reactjs/react-router/issues/586
 */
export function supportsHistory() {
  const ua = window.navigator.userAgent;

  if (
    (ua.indexOf('Android 2.') !== -1 || ua.indexOf('Android 4.0') !== -1) &&
    ua.indexOf('Mobile Safari') !== -1 &&
    ua.indexOf('Chrome') === -1 &&
    ua.indexOf('Windows Phone') === -1
  )
    return false;

  return window.history && 'pushState' in window.history;
}

/**
 * Returns true if browser fires popstate on hash change.
 * IE10 and IE11 do not.
 */
export function supportsPopStateOnHashChange() {
  return window.navigator.userAgent.indexOf('Trident') === -1;
}

/**
 * Returns false if using go(n) with hash history causes a full page reload.
 */
export function supportsGoWithoutReloadUsingHash() {
  return window.navigator.userAgent.indexOf('Firefox') === -1;
}

/**
 * Returns true if a given popstate event is an extraneous WebKit event.
 * Accounts for the fact that Chrome on iOS fires real popstate events
 * containing undefined state when pressing the back button.
 */
export function isExtraneousPopstateEvent(event) {
  event.state === undefined && navigator.userAgent.indexOf('CriOS') === -1;
}

export const canUseDOM = !!(
  typeof window !== 'undefined' &&
  window.document &&
  window.document.createElement
);

export function getConfirmation(message, callback) {
  callback(window.confirm(message)); // eslint-disable-line no-alert
}

/**
 * Returns true if the HTML5 history API is supported. Taken from Modernizr.
 *
 * https://github.com/Modernizr/Modernizr/blob/master/LICENSE
 * https://github.com/Modernizr/Modernizr/blob/master/feature-detects/history.js
 * changed to avoid false negatives for Windows Phones: https://github.com/reactjs/react-router/issues/586
 */
export function supportsHistory() {
  const ua = window.navigator.userAgent;

  if (
    (ua.indexOf('Android 2.') !== -1 || ua.indexOf('Android 4.0') !== -1) &&
    ua.indexOf('Mobile Safari') !== -1 &&
    ua.indexOf('Chrome') === -1 &&
    ua.indexOf('Windows Phone') === -1
  )
    return false;

  return window.history && 'pushState' in window.history;
}

/**
 * Returns true if browser fires popstate on hash change.
 * IE10 and IE11 do not.
 */
export function supportsPopStateOnHashChange() {
  return window.navigator.userAgent.indexOf('Trident') === -1;
}

/**
 * Returns false if using go(n) with hash history causes a full page reload.
 */
export function supportsGoWithoutReloadUsingHash() {
  return window.navigator.userAgent.indexOf('Firefox') === -1;
}

/**
 * Returns true if a given popstate event is an extraneous WebKit event.
 * Accounts for the fact that Chrome on iOS fires real popstate events
 * containing undefined state when pressing the back button.
 */
export function isExtraneousPopstateEvent(event) {
  return event.state === undefined && navigator.userAgent.indexOf('CriOS') === -1;
}

add 'return' modified: modules/DOMUtils.js