[FEATURE ui] Timezone override support

README.md

@@ -165,14 +165,22 @@ It fetches and refreshes PagerDuty schedules in the background using secret Page
 PagerDuty uses [Gravatar](https://en.gravatar.com/) to manage profile photos. 
 If you already have a Gravatar account, you can attach your PagerDuty login email to this account.
 
+### How can I set a custom timezone?
+By default From and To fields are displayed in the timezone of the schedule.  
+You can override this by adding `?timezone=value` to schedule URL. Use any timezone value [supported by luxon](https://github.com/moment/luxon/blob/master/docs/zones.md#specifying-a-zone). Examples:
+* Local to the client browser: /v1/schedules/PJ1P5JQ.html**?timezone=local**
+* UTC: /v1/schedules/PJ1P5JQ.html**?timezone=UTC**
+* Any UTC offset: /v1/schedules/PJ1P5JQ.html**?timezone=UTC+5**
+* Any [IANA Timezone](https://en.wikipedia.org/wiki/List_of_tz_database_time_zones): /v1/schedules/PJ1P5JQ.html**?timezone=Europe/Kiev**
+
 ## Contributing
 [Contribution guide](https://github.com/sergiitk/pagerbeauty/tree/master/CONTRIBUTING.md) and step-by-step local development instructions.  
 The source code of [Pager Beauty](https://github.com/sergiitk/pagerbeauty) is maintained by [@sergiitk](https://github.com/sergiitk).
 It's an Open Source project under MIT License. Contributions are welcomed. Follow the usual GitHub Pull Request process. [Be nice.](https://github.com/sergiitk/pagerbeauty/tree/master/CODE_OF_CONDUCT.md)
 
 ## Roadmap
-- `2019-04-01 – 2019-10-01`: Maintentnce mode: security and depdendency updates. Minor features, see Version 1.1.
-- `2019-10-01 — 2020-03-01`: Major features, see Version 2.0.
+- `2019-04-01 – 2019-10-01`: Maintentnce mode: security and depdendency updates.
+- `2020-10-01 — 2021-03-01`: Major features, see Version 2.0.
 
 #### Version 1.0
 
@@ -194,9 +202,6 @@ It's an Open Source project under MIT License. Contributions are welcomed. Follo
 - [x] Make on-call view red during an active incident
 - [x] HTTP authentication bypass support for embeds
 
-#### Version 1.1
-- [ ] [#102](https://github.com/sergiitk/pagerbeauty/issues/102) Ability to use browser local time
-
 #### Version 2.0
 - [ ] Built-in SSL Support
 - [ ] Next on duty

src/assets/javascripts/views/OnCallViews.jsx

@@ -429,9 +429,24 @@ export class OnCallDateTimeView extends React.Component {
   render() {
     const { date, timezone } = this.props;
     let dateInTz = date;
-    if (timezone) {
+
+    const urlParams = new URLSearchParams(window.location.search);
+    const tzOverride = urlParams.get('timezone');
+
+    if (tzOverride) {
+      dateInTz = date.setZone(tzOverride.replace(' ', '+'));
+    } else if (timezone) {
       dateInTz = date.setZone(timezone);
     }
+
+    if (!dateInTz.isValid) {
+      return (
+        <>
+          <span className="date_weekday">Incorrect Timezone</span>
+        </>
+      );
+    }
+
     return (
       <>
         <span className="date_weekday">{`${dateInTz.toFormat('EEEE')}, `}</span>

test/acceptance/oncall-P538IZH-custom-timezone.test.js

@@ -0,0 +1,31 @@
+// ------- Imports -------------------------------------------------------------
+
+import test from 'ava';
+import chai from 'chai';
+
+// ------- Internal imports ----------------------------------------------------
+
+import { AcceptanceHelpers } from '../helpers/AcceptanceHelpers';
+
+// ------- Init ----------------------------------------------------------------
+
+const { expect } = chai;
+const { waitFor } = AcceptanceHelpers;
+
+test.before(AcceptanceHelpers.openBrowser);
+test.serial.before(AcceptanceHelpers.openPage('/v1/schedules/P538IZH.html?timezone=UTC+2'));
+test.after.always(AcceptanceHelpers.closeBrowser);
+
+// ------- Tests ---------------------------------------------------------------
+
+test('On-Call P538IZH: Check page response', (t) => {
+  expect(t.context.pageResponse.ok()).to.be.true;
+});
+
+test('On-Call P538IZH: status row shows dates in custom timezone', waitFor('.schedule'), async (t) => {
+  const { pageTest } = t.context;
+  await pageTest.expectText('.date_start', 'From: Tuesday, Dec 25 7:00 AM');
+  await pageTest.expectText('.date_end', 'To: Tuesday, Dec 25 7:00 PM');
+});
+
+// ------- End -----------------------------------------------------------------

test/acceptance/oncall-PJ1P5JQ-no-end-date.test.js

@@ -55,7 +55,7 @@ test('On-Call PJ1P5JQ: show user avatar', waitFor('.schedule'), async (t) => {
 
 test('On-Call PJ1P5JQ: no end date in status row', waitFor('.schedule'), async (t) => {
   const { pageTest } = t.context;
-  await pageTest.expectText('.date_start', 'From: Tuesday, Dec 25 12:00 AM');
+  await pageTest.expectText('.date_start', 'From: Monday, Dec 24 9:00 PM');
   await pageTest.expectNoElements('.date_end');
 });
 

test/mocks/schedules/PJ1P5JQ/GET.mock

@@ -10,7 +10,7 @@ Cache-Control: max-age=0, private, must-revalidate
     "self": "https://api.pagerduty.com/schedules/PJ1P5JQ",
     "html_url": "https://apidocs.pagerduty.com/schedules/PJ1P5JQ",
     "name": "Schedule aliquid eum qui",
-    "time_zone": "America/New_York",
+    "time_zone": "America/Los_Angeles",
     "description": null,
     "users": [
       {