Automate the rotation of issue trage squad (#50526)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/50526

This change wants to automate the rotation of the issue triaging squad on Discord.
This is taking us a few minutes every week to rotate the oncall.

This change can save us some time.

The configuration file format is supposed to be like this:
```
{
  "userMap": {
     "discord-username1": "discord-id1",
     "discord-username2": "discord-id2",
     "discord-username3": "discord-id3",
     "discord-username4": "discord-id4"
   },
  "schedule": {
    "date1": ["discord-username1", "discord-username2"],
    "date2": ["discord-username3", "discord-username4"],
  }
}
```

## Changelog
[Internal] - Automate the issue triage oncall rotation

Reviewed By: cortinico

Differential Revision: D72569435

fbshipit-source-id: 435c13350cf503e99302775674e78a20e328e68d

.github/workflow-scripts/__tests__/extractIssueOncalls-test.js

@@ -0,0 +1,83 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+const {extractIssueOncalls} = require('../extractIssueOncalls');
+
+const userMap = {
+  '@g': '1785',
+  '@c': '1781',
+  '@s': '1272',
+  '@d': '1332',
+  '@m': '9555',
+  '@p': '6097',
+  '@f': '7565',
+};
+
+const schedule = {
+  '2025-04-01': ['@m', '@f'],
+  '2025-04-08': ['@g', '@d'],
+};
+
+describe('extractIssueOncalls', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+    jest.useFakeTimers('modern');
+  });
+
+  afterEach(() => {
+    jest.useRealTimers();
+  });
+  it('extracts m and f on 6 of April', () => {
+    jest.setSystemTime(new Date(2025, 3, 6));
+    const oncalls = extractIssueOncalls(schedule, userMap);
+    expect(oncalls).toEqual([userMap['@m'], userMap['@f']]);
+  });
+
+  it('extracts m and f on 7 of April', () => {
+    jest.setSystemTime(new Date(2025, 3, 7));
+    const oncalls = extractIssueOncalls(schedule, userMap);
+    expect(oncalls).toEqual([userMap['@m'], userMap['@f']]);
+  });
+
+  it('extracts g and d on 8 of April', () => {
+    jest.setSystemTime(new Date(2025, 3, 8));
+    const oncalls = extractIssueOncalls(schedule, userMap);
+    expect(oncalls).toEqual([userMap['@g'], userMap['@d']]);
+  });
+
+  it('extracts g and d on 9 of April', () => {
+    jest.setSystemTime(new Date(2025, 3, 9));
+    const oncalls = extractIssueOncalls(schedule, userMap);
+    expect(oncalls).toEqual([userMap['@g'], userMap['@d']]);
+  });
+
+  it('extracts g and d on 10 of April', () => {
+    jest.setSystemTime(new Date(2025, 3, 10));
+    const oncalls = extractIssueOncalls(schedule, userMap);
+    expect(oncalls).toEqual([userMap['@g'], userMap['@d']]);
+  });
+
+  it('extracts g and d on 11 of April', () => {
+    jest.setSystemTime(new Date(2025, 3, 11));
+    const oncalls = extractIssueOncalls(schedule, userMap);
+    expect(oncalls).toEqual([userMap['@g'], userMap['@d']]);
+  });
+
+  it('extracts g and d on 12 of April', () => {
+    jest.setSystemTime(new Date(2025, 3, 12));
+    const oncalls = extractIssueOncalls(schedule, userMap);
+    expect(oncalls).toEqual([userMap['@g'], userMap['@d']]);
+  });
+
+  it('extracts g and d on 13 of April', () => {
+    jest.setSystemTime(new Date(2025, 3, 13));
+    const oncalls = extractIssueOncalls(schedule, userMap);
+    expect(oncalls).toEqual([userMap['@g'], userMap['@d']]);
+  });
+});

.github/workflow-scripts/extractIssueOncalls.js

@@ -0,0 +1,61 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+const fs = require('fs');
+
+const MSEC_IN_DAY = 1000 * 60 * 60 * 24;
+
+function formatUsers(users) {
+  console.log(`${users[0]} ${users[1]}`.trim());
+}
+
+function extractUsersFromScheduleAndDate(schedule, userMap, date) {
+  const year = date.getFullYear();
+  const month = date.getMonth() + 1; // 0 is January, 1 is February
+  const day = date.getDate();
+  const dateStr = `${year}-${month < 10 ? `0${month}` : month}-${day < 10 ? `0${day}` : day}`;
+  const user1 = userMap[schedule[dateStr][0]];
+  const user2 = userMap[schedule[dateStr][1]];
+  return [user1, user2];
+}
+
+function main() {
+  const configuration = process.argv[2];
+  const {userMap, schedule} = JSON.parse(configuration);
+  extractIssueOncalls(schedule, userMap);
+}
+
+function extractIssueOncalls(schedule, userMap) {
+  const now = new Date();
+  const dayOfTheWeek = now.getDay(); // 0 is Sunday, 1 is Monday, etc.
+  let users;
+  if (dayOfTheWeek === 2) {
+    // exact match in the schedule
+    users = extractUsersFromScheduleAndDate(schedule, userMap, now);
+  } else if (dayOfTheWeek < 2) {
+    // sunday
+    // go to the tuesday of the last week
+    const lastWeekTuesday = new Date(now - (5 + dayOfTheWeek) * MSEC_IN_DAY);
+    users = extractUsersFromScheduleAndDate(schedule, userMap, lastWeekTuesday);
+  } else if (dayOfTheWeek > 1) {
+    // go to the previous tuesday
+    const thisWeekTuesday = new Date(now - (dayOfTheWeek - 2) * MSEC_IN_DAY);
+    users = extractUsersFromScheduleAndDate(schedule, userMap, thisWeekTuesday);
+  }
+  formatUsers(users);
+  return users;
+}
+
+if (require.main === module) {
+  void main();
+}
+
+module.exports = {
+  extractIssueOncalls,
+};