Advanced
Outcome: a PWA that uses platform capabilities — push, file handling, deeper OS integration — without breaking on the engines that lack them. The defining discipline at this level is progressive enhancement: every advanced capability is checked for support first and degrades cleanly when absent.
Do the core path first — Getting started, Installable, Offline, Performance — before reaching for these.
The rule for every advanced feature
Section titled “The rule for every advanced feature”-
Feature-detect, never assume. Guard each capability behind an
in/typeofcheck before using it. -
Verify real-world support. A capability existing in the spec is not the same as it working on your users’ browsers. Check the relevant Compatibility matrix — start from by-feature — before you depend on it.
-
Degrade cleanly. When a capability is missing, the app should lose that feature, not break. Plan the fallback before you ship the enhancement.
Capabilities to reach for
Section titled “Capabilities to reach for”Web Push notifications. Re-engage users with server-sent messages. Support and the iOS-installed-only constraints are real — read the web-push compatibility data and the notifications reference before building the subscription flow.
File System Access. Read and write user-chosen files for editor-like apps. This is one of the most unevenly supported capabilities, so a fallback (download/upload) is mandatory — see the File System Access reference and its compatibility data.
Background Sync. Defer and replay writes made while offline. Treat as enhancement; confirm support in the background-sync compatibility data.
Badging. Surface unread state on the app icon. Confirm via the badging compatibility data.
Production hardening
Section titled “Production hardening”- Service worker updates. Ship a deliberate update flow so users aren’t stranded on
a stale worker — the lifecycle reference
covers
waiting,skipWaiting, and update prompts. - Storage durability. Request persistent storage for data that must survive eviction; see storage persistence.
- Platform quirks. iOS diverges most; keep the iOS / Safari platform notes close.
Where to go next
Section titled “Where to go next”- Compatibility explorer — the support data behind every decision above.
- Capabilities reference — the advanced APIs in depth.
- Ecosystem — distribution and monetization once the app is production-ready.
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