Datetime polyfill, removed moment.tz.guess()

package.json

@@ -51,6 +51,7 @@
   },
   "dependencies": {
     "@expensify/react-native-web": "0.18.15",
+    "@formatjs/intl-datetimeformat": "^6.10.0",
     "@formatjs/intl-getcanonicallocales": "^2.2.0",
     "@formatjs/intl-listformat": "^7.2.2",
     "@formatjs/intl-locale": "^3.3.0",

src/libs/IntlPolyfill/index.js

@@ -7,4 +7,5 @@ import polyfillNumberFormat from './polyfillNumberFormat';
 export default function intlPolyfill() {
     // Just need to polyfill Intl.NumberFormat for web based platforms
     polyfillNumberFormat();
+    require('@formatjs/intl-datetimeformat');
 }

src/libs/IntlPolyfill/index.native.js

@@ -9,6 +9,7 @@ export default function polyfill() {
     require('@formatjs/intl-getcanonicallocales/polyfill');
     require('@formatjs/intl-locale/polyfill');
     require('@formatjs/intl-pluralrules/polyfill');
+    require('@formatjs/intl-datetimeformat');
     polyfillNumberFormat();
     polyfillListFormat();
 }

src/libs/Navigation/AppNavigator/AuthScreens.js

@@ -1,7 +1,6 @@
 import React from 'react';
 import Onyx, {withOnyx} from 'react-native-onyx';
 import PropTypes from 'prop-types';
-import moment from 'moment';
 import _ from 'underscore';
 import lodashGet from 'lodash/get';
 import withWindowDimensions, {windowDimensionsPropTypes} from '../../../components/withWindowDimensions';
@@ -64,7 +63,7 @@ Onyx.connect({
         }
 
         timezone = lodashGet(val, [currentAccountID, 'timezone'], {});
-        const currentTimezone = moment.tz.guess(true);
+        const currentTimezone = Intl.DateTimeFormat().resolvedOptions().timeZone;
 
         // If the current timezone is different than the user's timezone, and their timezone is set to automatic
         // then update their timezone.

src/libs/actions/App.js

@@ -1,4 +1,3 @@
-import moment from 'moment-timezone';
 import {AppState} from 'react-native';
 import Onyx from 'react-native-onyx';
 import lodashGet from 'lodash/get';
@@ -399,7 +398,7 @@ function openProfile(personalDetails) {
     if (lodashGet(oldTimezoneData, 'automatic', true)) {
         newTimezoneData = {
             automatic: true,
-            selected: moment.tz.guess(true),
+            selected: Intl.DateTimeFormat().resolvedOptions().timeZone,
         };
     }
 

src/pages/settings/Profile/TimezoneInitialPage.js

@@ -1,7 +1,6 @@
 import lodashGet from 'lodash/get';
 import React from 'react';
 import {View} from 'react-native';
-import moment from 'moment-timezone';
 import withCurrentUserPersonalDetails, {withCurrentUserPersonalDetailsPropTypes, withCurrentUserPersonalDetailsDefaultProps} from '../../../components/withCurrentUserPersonalDetails';
 import ScreenWrapper from '../../../components/ScreenWrapper';
 import HeaderWithBackButton from '../../../components/HeaderWithBackButton';
@@ -37,7 +36,7 @@ function TimezoneInitialPage(props) {
     const updateAutomaticTimezone = (isAutomatic) => {
         PersonalDetails.updateAutomaticTimezone({
             automatic: isAutomatic,
-            selected: isAutomatic ? moment.tz.guess() : timezone.selected,
+            selected: isAutomatic ? Intl.DateTimeFormat().resolvedOptions().timeZone : timezone.selected,
         });
     };