feat: release schedule

app/data/dash/chromium-schedule.ts

@@ -0,0 +1,54 @@
+import memoize from '@keyvhq/memoize';
+import { getKeyvCache } from '../cache';
+
+export interface ChromiumMilestoneSchedule {
+  earliestBeta: string; // YYYY-MM-DD
+  stableDate: string; // YYYY-MM-DD
+}
+
+interface ChromiumDashResponse {
+  mstones: Array<{
+    earliest_beta: string; // ISO timestamp
+    stable_date: string; // ISO timestamp
+    mstone: number;
+  }>;
+}
+
+/**
+ * Fetch Chromium milestone schedule from chromiumdash API.
+ * @param milestone - Chromium milestone number (e.g., 140)
+ * @returns Object with earliestBeta and stableDate in YYYY-MM-DD format
+ */
+export const getMilestoneSchedule = memoize(
+  async (milestone: number): Promise<ChromiumMilestoneSchedule> => {
+    const response = await fetch(
+      `https://chromiumdash.appspot.com/fetch_milestone_schedule?mstone=${milestone}`,
+    );
+
+    if (!response.ok) {
+      throw new Error(
+        `Failed to fetch Chromium schedule for milestone ${milestone}: ${response.status}`,
+      );
+    }
+
+    const data = (await response.json()) as ChromiumDashResponse;
+
+    if (!data.mstones || !Array.isArray(data.mstones) || data.mstones.length === 0) {
+      throw new Error(`No schedule data found for Chromium milestone ${milestone}`);
+    }
+
+    const schedule = data.mstones[0];
+
+    return {
+      earliestBeta: schedule.earliest_beta.split('T')[0],
+      stableDate: schedule.stable_date.split('T')[0],
+    };
+  },
+  getKeyvCache('chromium-schedule'),
+  {
+    // Cache for 6 hours
+    ttl: 6 * 60 * 60 * 1_000,
+    // At 5 hours, refetch but serve stale data
+    staleTtl: 60 * 60 * 1_000,
+  },
+);

app/data/release-schedule.ts

@@ -0,0 +1,231 @@
+import { parse as parseSemver } from 'semver';
+import memoize from '@keyvhq/memoize';
+import { ElectronRelease, getReleasesOrUpdate } from './release-data';
+import { extractChromiumMilestone, extractNodeVersion, getPrereleaseType } from '~/helpers/version';
+import { getMilestoneSchedule } from './dash/chromium-schedule';
+import { getKeyvCache } from './cache';
+
+export interface MajorReleaseSchedule {
+  version: string; // `${major}.0.0`
+  alphaDate: string | null; // YYYY-MM-DD -- some old versions didn't have alpha releases
+  betaDate: string; // YYYY-MM-DD
+  stableDate: string; // YYYY-MM-DD
+  eolDate: string; // YYYY-MM-DD
+  chromiumVersion: number; // milestone, aka major version
+  nodeVersion: string; // `${major}.${minor}`
+  status: 'active' | 'prerelease' | 'eol';
+}
+
+type AbsoluteMajorReleaseSchedule = Omit<MajorReleaseSchedule, 'status'>;
+
+interface MajorReleaseGroup {
+  major: number;
+  releases: ElectronRelease[];
+  firstStable?: ElectronRelease; // Only used for Chromium milestone extraction
+}
+
+const SCHEDULE_OVERRIDES: Map<string, Partial<AbsoluteMajorReleaseSchedule>> = new Map([
+  [
+    '2.0.0',
+    {
+      betaDate: '2018-02-21',
+      stableDate: '2018-05-01',
+    },
+  ],
+  [
+    '3.0.0',
+    {
+      betaDate: '2018-06-21',
+      stableDate: '2018-09-18',
+    },
+  ],
+  [
+    '4.0.0',
+    {
+      betaDate: '2018-10-11',
+      stableDate: '2018-12-20',
+    },
+  ],
+  [
+    '5.0.0',
+    {
+      betaDate: '2019-01-22',
+      stableDate: '2019-04-23',
+    },
+  ],
+  [
+    '6.0.0',
+    {
+      betaDate: '2019-04-25',
+    },
+  ],
+  [
+    '15.0.0',
+    {
+      alphaDate: '2021-07-20',
+    },
+  ],
+]);
+
+// Determine support window: 4 for v12-15, 3 for the rest
+const getSupportWindow = (major: number): number => {
+  return major >= 12 && major <= 15 ? 4 : 3;
+};
+
+/**
+ * Get absolute schedule data (cacheable, not time-dependent).
+ */
+export const getAbsoluteSchedule = memoize(
+  async (): Promise<AbsoluteMajorReleaseSchedule[]> => {
+    const allReleases = await getReleasesOrUpdate();
+
+    // Group releases by major version (filter to >= 2)
+    const majorGroups = new Map<number, MajorReleaseGroup>();
+
+    for (const release of allReleases) {
+      const major = parseSemver(release.version)?.major;
+      if (!major || major < 2) continue;
+
+      if (!majorGroups.has(major)) {
+        majorGroups.set(major, { major, releases: [] });
+      }
+
+      const group = majorGroups.get(major)!;
+      group.releases.push(release);
+
+      const prereleaseType = getPrereleaseType(release.version);
+
+      // Track first stable release (last in iteration = first chronologically)
+      // Only used for extracting Chromium milestone
+      if (prereleaseType === 'stable') {
+        group.firstStable = release;
+      }
+    }
+
+    // Build milestone map in forward pass
+    const milestoneMap = new Map<number, number>();
+    const sortedMajors = Array.from(majorGroups.keys()).sort((a, b) => a - b);
+
+    for (const major of sortedMajors) {
+      const group = majorGroups.get(major)!;
+
+      if (group.firstStable) {
+        // Use actual Chromium version from stable release
+        const milestone = extractChromiumMilestone(group.firstStable.chrome);
+        milestoneMap.set(major, milestone);
+      } else {
+        // Estimate: M(V) = M(V-1) + 2
+        const prevMajor = major - 1;
+        const prevMilestone = milestoneMap.get(prevMajor);
+
+        if (!prevMilestone) {
+          throw new Error(
+            `Cannot determine Chromium milestone for Electron ${major}: no stable release and no previous milestone`,
+          );
+        }
+
+        milestoneMap.set(major, prevMilestone + 2);
+      }
+    }
+
+    // Build absolute schedule data for each major
+    const schedule: AbsoluteMajorReleaseSchedule[] = [];
+
+    for (const major of sortedMajors) {
+      const milestone = milestoneMap.get(major)!;
+      const chromiumSchedule = await getMilestoneSchedule(milestone);
+
+      // Alpha: previous major's stable + 2 days (null for v14 and earlier)
+      let alphaDate: string | null = null;
+      if (major > 14) {
+        const prevMilestone = milestoneMap.get(major - 1)!;
+        const prevSchedule = await getMilestoneSchedule(prevMilestone);
+
+        // Add 2 days to previous stable date
+        const prevStable = new Date(prevSchedule.stableDate + 'T00:00:00');
+        prevStable.setDate(prevStable.getDate() + 2);
+        alphaDate = prevStable.toISOString().split('T')[0];
+      }
+
+      const latestRelease = majorGroups.get(major)!.releases[0];
+      const nodeVersion = extractNodeVersion(latestRelease.node);
+
+      const entry: AbsoluteMajorReleaseSchedule = {
+        version: `${major}.0.0`,
+        alphaDate,
+        betaDate: chromiumSchedule.earliestBeta,
+        stableDate: chromiumSchedule.stableDate,
+        chromiumVersion: milestone,
+        nodeVersion,
+        eolDate: '', // Placeholder, will be calculated
+      };
+
+      // Apply overrides early so they cascade to dependent calculations (e.g. EOL)
+      const override = SCHEDULE_OVERRIDES.get(entry.version);
+      if (override) {
+        Object.assign(entry, override);
+      }
+
+      schedule.push(entry);
+    }
+
+    // Calculate EOL dates
+    for (const entry of schedule) {
+      const major = parseInt(entry.version.split('.')[0], 10);
+      const eolMajor = major + getSupportWindow(major);
+      const eolEntry = schedule.find((r) => r.version === `${eolMajor}.0.0`);
+
+      if (eolEntry) {
+        entry.eolDate = eolEntry.stableDate;
+      } else {
+        // Extrapolate for future versions
+        const maxMajor = Math.max(...schedule.map((r) => parseInt(r.version.split('.')[0], 10)));
+        const maxEntry = schedule.find((r) => r.version === `${maxMajor}.0.0`)!;
+        const milestone = maxEntry.chromiumVersion + (eolMajor - maxMajor) * 2; // 2 milestones per major
+        const eolSchedule = await getMilestoneSchedule(milestone);
+        entry.eolDate = eolSchedule.stableDate;
+      }
+    }
+
+    return schedule;
+  },
+  getKeyvCache('absolute-schedule'),
+  {
+    // Cache for 60 seconds
+    ttl: 60_000,
+    // At 10 seconds, refetch but serve stale data
+    staleTtl: 10_000,
+  },
+);
+
+/**
+ * Get relative schedule data (time-dependent, includes status and EOL).
+ */
+export async function getRelativeSchedule(): Promise<MajorReleaseSchedule[]> {
+  // Find latest major version
+  const allReleases = await getReleasesOrUpdate();
+  const latestStableMajor = parseInt(
+    allReleases
+      .find((release) => getPrereleaseType(release.version) === 'stable')
+      ?.version.split('.')[0] || '0',
+    10,
+  );
+
+  const absoluteData = await getAbsoluteSchedule();
+  const supportWindow = getSupportWindow(latestStableMajor);
+  const minActiveMajor = latestStableMajor - supportWindow + 1;
+
+  const schedule: MajorReleaseSchedule[] = absoluteData.map((entry) => {
+    const major = parseInt(entry.version.split('.')[0], 10);
+    const status =
+      major > latestStableMajor ? 'prerelease' : major >= minActiveMajor ? 'active' : 'eol';
+    return { ...entry, status };
+  });
+
+  // Sort descending by major version
+  return schedule.sort((a, b) => {
+    const aMajor = parseInt(a.version.split('.')[0], 10);
+    const bMajor = parseInt(b.version.split('.')[0], 10);
+    return bMajor - aMajor;
+  });
+}

app/helpers/version.ts

@@ -0,0 +1,46 @@
+import { parse as parseSemver } from 'semver';
+
+/**
+ * Get the prerelease type from a version string.
+ * @returns 'alpha', 'beta', 'nightly', 'stable', or undefined for unknown prerelease types
+ */
+export function getPrereleaseType(
+  version: string,
+): 'alpha' | 'beta' | 'nightly' | 'stable' | undefined {
+  const parsed = parseSemver(version);
+  if (!parsed || parsed.prerelease.length === 0) {
+    return 'stable';
+  }
+  const prereleaseType = parsed.prerelease[0];
+  if (prereleaseType === 'alpha' || prereleaseType === 'beta' || prereleaseType === 'nightly') {
+    return prereleaseType;
+  }
+  // Silently ignore unknown prerelease types
+  return undefined;
+}
+
+/**
+ * Extract Node.js major.minor version from a Node version string.
+ * @param nodeString - Node version string like "20.11.1" or "22.14.0"
+ * @returns Node version in "major.minor" format like "20.11"
+ */
+export function extractNodeVersion(nodeString: string): string {
+  const parts = nodeString.split('.');
+  if (parts.length < 2) {
+    throw new Error(`Invalid Node.js version string: ${nodeString}`);
+  }
+  return `${parts[0]}.${parts[1]}`;
+}
+
+/**
+ * Extract Chromium milestone (major version) from a Chrome version string.
+ * @param chromeString - Chrome version string like "116.0.5845.190"
+ * @returns Chromium milestone like 116
+ */
+export function extractChromiumMilestone(chromeString: string): number {
+  const milestone = parseInt(chromeString.split('.')[0], 10);
+  if (isNaN(milestone)) {
+    throw new Error(`Invalid Chrome version string: ${chromeString}`);
+  }
+  return milestone;
+}

app/root.tsx

@@ -3,7 +3,7 @@ import type { LinksFunction } from '@remix-run/node';
 
 import './tailwind.css';
 import { Logo } from '~/components/Logo';
-import { ArrowUpRight, History, Search } from 'lucide-react';
+import { ArrowUpRight, History, Search, CalendarPlus } from 'lucide-react';
 import { useEffect } from 'react';
 
 export const links: LinksFunction = () => [];
@@ -22,6 +22,15 @@ const nav = [
     ),
     path: '/history',
   },
+  {
+    title: (
+      <>
+        <CalendarPlus className="w-4 h-4" />
+        Schedule
+      </>
+    ),
+    path: '/schedule',
+  },
   {
     title: (
       <>

app/routes.ts

@@ -28,4 +28,5 @@ export default [
     route('compare/:fromVersion/:toVersion', 'routes/release/compare.tsx'),
     route(':version', 'routes/release/single.tsx'),
   ]),
+  route('schedule', 'routes/schedule.tsx'),
 ] satisfies RouteConfig;

app/routes/history.tsx

@@ -206,7 +206,7 @@ export default function ReleaseHistory() {
       </div>
 
       <div className="bg-white dark:bg-gray-800 rounded-xl shadow-sm border border-gray-200 dark:border-gray-700 overflow-hidden mb-6">
-        <div className="p-4 border-b border-gray-200 dark:border-gray-700 bg-gray-50 dark:bg-gray-900/50 flex flex-wrap items-center gap-6">
+        <div className="p-4 border-gray-200 dark:border-gray-700 bg-gray-50 dark:bg-gray-900/50 flex flex-wrap items-center gap-6">
           <div className="flex items-center gap-2">
             <div className="w-3 h-3 rounded-full bg-green-500"></div>
             <span className="text-sm text-gray-700 dark:text-gray-300">Stable Release</span>