Feature support·Attar, Attar AOT and Attar Electron·reviewed

Can I use it in Attar?

HTML, CSS, JavaScript, React, Node.js and desktop APIs, in one map. Every feature carries a support state, a note that says what the state covers, and the date it was assessed.

353features across the Attar platformElectron 37.2.4 · Node 22.17.1 · reviewed
Supported 27Partial support 134Not supported 180Not planned 12
How to read it

Four states. Each one is a claim you can check.

A state applies to the scope in the feature's note, not to the whole area the name suggests. Counts are not completion percentages, and the map is not a certification of the current packaged release.

Supported

The named scope has recorded checks. It is not whole-area certification.

Partial support

A limited implementation exists. The note names its limits.

Not supported

Not offered as supported in the current profile: implementation or validation is missing. It does not say the code is absent.

Not planned

Excluded by an accepted design decision. Reversing it takes a design change, not a ticket. Unconfirmed work never lands here.

The map

353 features, three components.

Pick a component, pick a state, or search a name. Attar is the native UI runtime; Attar AOT compiles the JavaScript; Attar Electron serves an existing Electron app.

353 features
Feature · area · componentSupport
@electron/remote compatibilityBuild & tools · Attar ElectronPartial support

Admitted facade slice; full parity unverified

Assessment: 2026-09-12
AbortController and AbortSignalWeb APIs · AttarPartial support

Blink owns abort state, its event and listener cancellation; JavaScript keeps the reason and callback identity. Native bridge tests cover duplicate, once and nested aborts.

Assessment: 2026-09-16
AccessibilityUI · AttarSupported

The native accessibility tree is measured: 65 nodes with roles, names and states, buttons actionable through the Accessibility API. Not a WCAG conformance claim.

Assessment: 2026-09-16
addEventListener on DOM nodesWeb APIs · AttarPartial support

addEventListener, removeEventListener and dispatchEvent go to Blink's own listener list, including capture, once, passive and AbortSignal cancellation. Regression cases cover removal during delivery and stopImmediatePropagation.

Assessment: 2026-09-16
Ahead-of-time JavaScript compilationJavaScript · Attar AOTSupported

The pinned Static Hermes toolchain compiles the whole application graph ahead of time; the certified app runs from it, and the full Test262 run (102,619 variants, 2026-09-14) measures the engine.

Assessment: 2026-09-16
appElectron APIs · Attar ElectronPartial support

Readiness/lifecycle slice; some app operations refused

Assessment: 2026-09-12
assertNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

assert/strictNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

Async IPC admission / repliesBuild & tools · Attar ElectronSupported

Production-extracted fixture passed

Assessment: 2026-09-12
async_hooksNode.js · Attar ElectronPartial support

Timer-local context slice; public hooks incomplete

Asynchronous context trackingNode.js · Attar ElectronPartial support

Scoped host/engine adapters; complete Node parity pending

Audio and video elementsUI · AttarNot supported

audio and video elements are outside the current profile (CP1008); a future profile may add controls and open codecs.

Assessment: 2026-09-16
autoUpdaterElectron APIs · Attar ElectronPartial support

Squirrel path; open-window install handshake missing

Assessment: 2026-09-12
BaseWindowElectron APIs · Attar ElectronPartial support

Existing native window; full window API pending

Assessment: 2026-09-12
BrowserViewElectron APIs · Attar ElectronNot supported

Wrapper reaches unavailable WebContentsView

Assessment: 2026-09-12
BrowserWindowElectron APIs · Attar ElectronPartial support

One Views owner; additional windows refused

Assessment: 2026-09-12
bufferNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

Bundled assetsBuild & tools · AttarSupported

Build-time assets (fonts, images, data files) ship inside the application graph, as in the certified app; format support follows the native provider that reads them.

Assessment: 2026-09-16
C/C++ addons with Node-APINode.js · Attar ElectronNot supported

Arbitrary native addon loading/ABI not admitted

C++ addonsNode.js · Attar ElectronNot supported

Arbitrary native addon loading/ABI not admitted

Canvas 2D JavaScript bindingsUI · AttarNot supported

No getContext bridge is exposed by the inspected UI wrapper. Chromium source availability alone does not expose this API.

Assessment: 2026-09-13
child_processNode.js · Attar ElectronPartial support

OS process adapter; full Node I/O parity pending

Chrome UI / browser process / contentDesign · AttarNot planned

Excluded from the native product; remote content uses the System WebView boundary

Assessment: 2026-09-12

Excluded by an accepted design decision; this is not an implementation backlog item.

classList and DOMTokenListWeb APIs · AttarPartial support

Blink parses, validates and mutates the token list: add, remove, toggle, replace, live iteration and the DOM exceptions. Native bridge tests cover the contract.

Assessment: 2026-09-16
clipboardElectron APIs · Attar ElectronPartial support

Host protocol; formats/platform parity pending

Assessment: 2026-09-12
clusterNode.js · Attar ElectronNot supported

Not offered as supported in the current profile. Source imported; cluster runtime unverified

Command-line optionsNode.js · Attar ElectronNot supported

Not offered as supported in the current profile. Separate runtime/API contract; complete coverage pending

Component dependency isolationBuild & tools · AttarSupported

Dependency/embedding checks passed; synthetic boundary

Assessment: 2026-09-12
consoleNode.js · Attar ElectronNot supported

Not offered as supported in the current profile. Full module behavior not certified; provider coverage pending

constantsNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

contentTracingElectron APIs · Attar ElectronNot supported

native provider missing

Assessment: 2026-09-12
contextBridgeElectron APIs · Attar ElectronNot supported

native provider missing

Assessment: 2026-09-12
crashReporterElectron APIs · Attar ElectronNot supported

native provider missing

Assessment: 2026-09-12
cryptoNode.js · Attar ElectronPartial support

Primitive providers; pinned callers/native parity pending

CSS AnimationUI · AttarPartial support

Blink's animation engine ships and passes 197 of 199 official CSS animation tests on Attar's own engine build; the certified app carries one keyframe spinner. Animation progress inside a packaged app is unmeasured, and the current profile still lists CSS animations outside its scope.

Assessment: 2026-09-16
CSS Flexible Box Layout ModuleUI · AttarSupported

display: flex and inline-flex, gap, justify-content and align-items are in the profile and lay out the certified app through Blink (16 screens at pixel parity).

Assessment: 2026-09-16
CSS Grid LayoutUI · AttarPartial support

display: grid and the grid-template properties are in the profile, and Blink lays them out: 2,230 of 2,249 official CSS Grid tests pass on Attar's own engine build. That run measures the engine, not a packaged Attar application.

Assessment: 2026-09-16
CSS imports in standalone UI bundlesBuild & tools · AttarNot supported

The standalone bundler rejects CSS imports; use explicit --stylesheet inputs in cascade order.

Assessment: 2026-09-13
CSS TransitionsUI · AttarPartial support

transition-duration is in the profile, Blink's transition engine ships and the native runtime has a passing transitions case in the pinned SDK. The certified Electron app deliberately ports no transition, so none is measured there.

Assessment: 2026-09-16
dataset and data attributesWeb APIs · AttarPartial support

Blink owns the data attribute map and its key conversion; the wrapper only projects it. Native bridge tests cover enumeration and key names.

Assessment: 2026-09-16
DebuggerNode.js · Attar ElectronNot planned

Node/V8 debugger backend excluded; does not exclude external build tooling

Assessment: 2026-09-12

Excluded by an accepted design decision; this is not an implementation backlog item.

desktopCapturerElectron APIs · Attar ElectronNot supported

native provider missing

Assessment: 2026-09-12
DevTools / debuggingBuild & tools · Attar ElectronNot supported

Not offered as supported in the current profile. No complete Electron-equivalent tooling result catalogued

Assessment: 2026-09-12
dgramNode.js · Attar ElectronNot supported

Not offered as supported in the current profile. Source imported; complete UDP provider unverified

diagnostics_channelNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

dialogElectron APIs · Attar ElectronPartial support

Native Electron dialog bindings exist. Full option coverage, cancellation and packaged parity remain pending.

Assessment: 2026-09-13
dnsNode.js · Attar ElectronPartial support

Resolver bindings; complete native DNS path unverified

dns/promisesNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

DOM eventsNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

domainNode.js · Attar ElectronNot supported

Not offered as supported in the current profile. Full module behavior not certified; provider coverage pending

Element attributesUI · AttarPartial support

Selected attribute reads and writes are exposed. Inline style updates remain rejected.

Assessment: 2026-09-13
Engine embeddingJavaScript · Attar AOTPartial support

Runtime allocation and admission are shared; consumers own their runtime instances.

Assessment: 2026-09-13
ErrorsNode.js · Attar ElectronNot supported

Not offered as supported in the current profile. Separate runtime/API contract; complete coverage pending

eval / new FunctionDesign · Attar AOTNot planned

Runtime compilation of new JavaScript excluded; ordinary precompiled JS remains supported

Assessment: 2026-09-12

Excluded by an accepted design decision; this is not an implementation backlog item.

fsNode.js · Attar ElectronPartial support

I/O/admin providers; native reuse and method gaps

fs/promisesNode.js · Attar ElectronPartial support

Async bridge; final native product proof pending

Garbage collectionJavaScript · Attar AOTSupported

The AOT runtime keeps Hermes garbage collection and rooting; idle full GC is measured at the engine boundary.

Assessment: 2026-09-16
getBoundingClientRect()UI · AttarPartial support

Native geometry is exposed on admitted node wrappers; this is not the full CSSOM.

Assessment: 2026-09-13
getComputedStyle()UI · AttarPartial support

getComputedStyle reads Blink's own computed style; nothing is cached on the JavaScript side and computed declarations refuse writes. The native runtime case passes in the pinned SDK. Not certified in a packaged application.

Assessment: 2026-09-16
GlobalsNode.js · Attar ElectronPartial support

Scoped host/engine adapters; complete Node parity pending

globalShortcutElectron APIs · Attar ElectronNot supported

native provider missing

Assessment: 2026-09-12
HTML compilationBuild & tools · AttarSupported

Static HTML known at build time compiles into the native document; measured on the certified Etcher build (5 of 5 journeys equivalent to Electron, 2026-09-04). Markup from runtime strings is excluded by design.

Assessment: 2026-09-16
HTMLElement.focus()UI · AttarSupported

Element focus, Tab order and focus events are in the profile and were measured in the human pass: Tab keeps focus inside the web area and the focused button state renders.

Assessment: 2026-09-16
httpNode.js · Attar ElectronPartial support

Pinned source; parser/transport provider closure pending

http2Node.js · Attar ElectronPartial support

Pinned source; native transport closure pending

httpsNode.js · Attar ElectronPartial support

Pinned Node TLS/HTTP; providers incomplete

Images and UI resource URLsUI · AttarSupported

Bundled images and data URLs are in the profile. SVG as image is measured: 39 of 39 corpus items match stock Chromium, plus the logo journeys. Other formats decode through Blink and are not measured separately.

Assessment: 2026-09-16
ImageViewElectron APIs · Attar ElectronNot supported

native provider missing

Assessment: 2026-09-12
Imperative DOM creationWeb APIs · AttarPartial support

document.createElement, createTextNode and createDocumentFragment build real Blink nodes outside React, and getElementsByTagName returns a live collection. The element names follow the SDK's admitted set.

Assessment: 2026-09-16
inAppPurchaseElectron APIs · Attar ElectronNot supported

native provider missing

Assessment: 2026-09-12
inspectorNode.js · Attar ElectronNot planned

V8 inspector backend excluded from the shipped AOT runtime

Assessment: 2026-09-12

Excluded by an accepted design decision; this is not an implementation backlog item.

inspector/promisesNode.js · Attar ElectronNot planned

V8 inspector backend excluded from the shipped AOT runtime

Assessment: 2026-09-12

Excluded by an accepted design decision; this is not an implementation backlog item.

InternationalizationNode.js · Attar ElectronPartial support

Scoped host/engine adapters; complete Node parity pending

Internationalization APIJavaScript · Attar AOTPartial support

Intl is partial: Collator 91 % of Test262 files, NumberFormat 49 %, DateTimeFormat 42 %, PluralRules and Segmenter below 6 %, Locale 0 %. The compile-time message catalogue and runtime locale are in the profile.

Assessment: 2026-09-16
ipcMainElectron APIs · Attar ElectronPartial support

Async handlers; product IPC/serialization proof pending

Assessment: 2026-09-12
ipcRendererElectron APIs · Attar ElectronPartial support

Async slice; synchronous IPC refused

Assessment: 2026-09-12
JavaScript classesJavaScript · Attar AOTSupported

Classes, inheritance, private fields and methods: 98.7 % of Test262 class files pass. The remaining failures are private-accessor edge cases and decorators, a proposal outside ECMAScript.

Assessment: 2026-09-16
JavaScript functions and closuresJavaScript · Attar AOTSupported

Functions, closures, arrow functions, destructuring and generators: 99 % of the Test262 files in these suites pass. The language suite as a whole is 95 % clean once accepted boundaries (eval, with, dynamic import) and unverifiable negative tests are set aside.

Assessment: 2026-09-16
JavaScript modulesJavaScript · Attar AOTSupported

Static imports resolve at build time into the locked graph, as in the certified app. Top-level await and the Test262 module-code suite go through a separate pipeline boundary and are not measured.

Assessment: 2026-09-16
keytar / OS keychainBuild & tools · Attar ElectronPartial support

Native provider/owner; current product proof pending

Assessment: 2026-09-12
Linux packagesBuild & tools · AttarPartial support

The Linux developer packages are published for x86_64: apt-get install on Ubuntu and Debian, install.sh on Arch. Install, build, edit, rebuild and four window checks pass their scoped criteria. No Linux product artifact has a verified acceptance run.

Assessment: 2026-09-16
Local HTML child documentBuild & tools · Attar ElectronPartial support

Bounded profile; parsed scripts do not execute

Assessment: 2026-09-12
Locked application graphBuild & tools · AttarSupported

Every import and resource resolves at build time into a finite graph; an unknown module or symbol is a build error. This is how the certified app is built.

Assessment: 2026-09-16
macOS app packagingBuild & tools · AttarSupported

The composed Electron app packages as a macOS .app and .dmg, ad-hoc signed; the standalone builder now produces a signed .app of its own. Notarized release evidence is separate.

Assessment: 2026-09-16
macOS signing and notarizationBuild & tools · AttarPartial support

Ad-hoc signing is measured on the certified artifact. Developer ID signing and notarization gates exist, but no notarized release is recorded.

Assessment: 2026-09-16
Main worker schedulingBuild & tools · Attar ElectronPartial support

Owner loop present; packaged responsiveness unverified

Assessment: 2026-09-12
matchMedia and media queriesWeb APIs · AttarPartial support

matchMedia returns a live MediaQueryList with matches, addEventListener and the legacy addListener. Measured by the native media-query case in the pinned SDK.

Assessment: 2026-09-16
MathMLUI · AttarNot supported

MathML is not in the current profile and no Attar run renders it.

Combines 2 related entries for this feature.

Assessment: 2026-09-16
MenuElectron APIs · Attar ElectronPartial support

Earlier macOS live result; parity gaps remain

Assessment: 2026-09-12
MenuItemElectron APIs · Attar ElectronPartial support

Template/role logic; platform parity pending

Assessment: 2026-09-12
MessageChannelMainElectron APIs · Attar ElectronNot supported

native provider missing

Assessment: 2026-09-12
moduleNode.js · Attar ElectronPartial support

Closed graph; arbitrary runtime module loading unavailable

Modules: CommonJS modulesNode.js · Attar ElectronPartial support

Closed build graph only; runtime loading is restricted

Modules: ECMAScript modulesNode.js · Attar ElectronPartial support

Closed build graph only; runtime loading is restricted

Modules: PackagesNode.js · Attar ElectronPartial support

Closed build graph only; runtime loading is restricted

Modules: TypeScriptNode.js · Attar ElectronPartial support

Closed build graph only; runtime loading is restricted

Multiple native windowsBuild & tools · Attar ElectronNot supported

Additional native BrowserWindow creation refused

Assessment: 2026-09-12
MutationObserverUI · AttarPartial support

MutationObserver delivers Blink's own mutation records. The native runtime case passes; an observer option-conversion correction is still open, and a packaged shadcn run still reports it missing on an older seal.

Assessment: 2026-09-16
Native addon admissionBuild & tools · Attar ElectronNot supported

Each addon needs its own ABI/loading/lifetime contract

Assessment: 2026-09-12
Native C / Rust UI APIBuild & tools · AttarPartial support

Core has an engine-free interface. Current standalone distribution still needs validation.

Assessment: 2026-09-13
Native layer seal / distributionBuild & tools · Attar ElectronNot supported

Contract staged; archive unpublished

Assessment: 2026-09-12
Native menus and dialogsUI · AttarPartial support

Native dialogs are measured: modal open and cancel, the file panel. The application menu is empty and Cmd+Q does not quit (issue 67).

Assessment: 2026-09-16
Native SDK distributionBuild & tools · AttarPartial support

Sealed SDK tooling exists; a clean-machine standalone distribution is not proven.

Assessment: 2026-09-13
Native windowsUI · AttarPartial support

One native window per app is measured, for the certified Electron app (fixed size, 800 by 480) and for the standalone examples. Additional windows and resizing are refused.

Assessment: 2026-09-16
nativeImageElectron APIs · Attar ElectronNot supported

native provider missing

Assessment: 2026-09-12
nativeThemeElectron APIs · Attar ElectronPartial support

Electron native appearance implementation and UI-thread routing exist; full event parity and packaged validation remain pending.

Assessment: 2026-09-13
netElectron APIs · Attar ElectronPartial support

Chromium carve tested; final product integration pending

Assessment: 2026-09-12
netNode.js · Attar ElectronPartial support

TCP providers; complete socket semantics unverified

netLogElectron APIs · Attar ElectronNot supported

Not offered as supported in the current profile. Facade source; native logging path unverified

Assessment: 2026-09-12
NotificationElectron APIs · Attar ElectronNot supported

native provider missing

Assessment: 2026-09-12
One-command standalone app packagingBuild & tools · AttarPartial support

attar build now composes a standalone signed macOS arm64 app with no Electron and no Node. The Notes and Panels examples build, sign and start. Clean-machine execution and an acceptance run are not verified.

Assessment: 2026-09-16
osNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

OS process isolationBuild & tools · Attar ElectronNot planned

Main/renderer OS isolation excluded by the one-process design; child_process is separate

Assessment: 2026-09-12

Excluded by an accepted design decision; this is not an implementation backlog item.

Packaged acceptance / platformsBuild & tools · Attar ElectronNot supported

Current package unverified; old snapshot is not current

Assessment: 2026-09-12
pathNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

path/posixNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

path/win32Node.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

perf_hooksNode.js · Attar ElectronPartial support

Clock slice; messaging/Undici bootstrap gap

PermissionsNode.js · Attar ElectronNot supported

Not offered as supported in the current profile. Separate runtime/API contract; complete coverage pending

Pointer captureWeb APIs · AttarPartial support

setPointerCapture, releasePointerCapture and hasPointerCapture are bound to the native adapter. Packaged pointer checks still have open failures in component scenarios.

Assessment: 2026-09-16
powerMonitorElectron APIs · Attar ElectronPartial support

OS state/events provider; full parity pending

Assessment: 2026-09-12
powerSaveBlockerElectron APIs · Attar ElectronPartial support

Sleep inhibitor slice; full type/platform coverage pending

Assessment: 2026-09-12
Preload lifecycle / isolationBuild & tools · Attar ElectronNot supported

Isolated worlds and preload guarantees not established

Assessment: 2026-09-12
processNode.js · Attar ElectronPartial support

Metadata/metrics methods; full Node process API pending

Promises and async / awaitJavaScript · Attar AOTSupported

Promises and async/await: 98 % of Promise files and 94 % of async-function files pass Test262; job scheduling belongs to the embedding host. Promise.allKeyed is a proposal outside the boundary.

Assessment: 2026-09-16
protocolElectron APIs · Attar ElectronNot supported

native provider missing

Assessment: 2026-09-12
punycodeNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

pushNotificationsElectron APIs · Attar ElectronPartial support

APNS provider interface; live delivery unverified

Assessment: 2026-09-12
querySelector() / querySelectorAll()UI · AttarPartial support

querySelector and querySelectorAll run Blink's own selector engine over the live tree and return a NodeList. Measured by the native runtime cases in the pinned SDK; not certified in a packaged application.

Assessment: 2026-09-16
querystringNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

ReactReact · AttarSupported

React 19.3.0 on reconciler 0.34.0 for standalone apps, React 17.0.2 for the certified Electron app. Both run on the same native reconciler host.

Assessment: 2026-09-16
React class componentsReact · AttarNot supported

The pinned reconciler carries the class-component path, but the current profile lists class components outside its scope (CP1012) and no Attar application exercises it.

Assessment: 2026-09-16
React concurrent rendering / SuspenseReact · AttarNot supported

Suspense and concurrent rendering stay outside the current profile (CP1012), even though the standalone host now pins React 19.

Assessment: 2026-09-16
React hooks and stateReact · AttarSupported

useState and useEffect drive the certified app's screens; the standalone host runs the same hooks on React 19. Other hooks run on the same reconciler and are not measured separately.

Assessment: 2026-09-16
React hydrationReact · AttarNot supported

The current React host declares supportsHydration: false.

Assessment: 2026-09-13
React style prop / inline stylesUI · AttarNot supported

The React style prop is still refused by the SDK the toolchain pins. Blink-side declaration updates and native inline-style properties exist in source and pass a native case; their sealed build and differential evidence are the remaining step.

Assessment: 2026-09-16
readlineNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

readline/promisesNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

Regular expressionsJavaScript · Attar AOTPartial support

91 % of Test262 RegExp files pass. The v flag (unicodeSets) is not supported; some named-group and character-class-escape cases fail.

Assessment: 2026-09-16
Remote System WebViewBuild & tools · Attar ElectronPartial support

UI belongs to Attar; embedding integration incomplete

Assessment: 2026-09-12
replNode.js · Attar ElectronNot planned

Interactive JavaScript evaluation excluded from the closed AOT graph

Assessment: 2026-09-12

Excluded by an accepted design decision; this is not an implementation backlog item.

ReportNode.js · Attar ElectronNot supported

Not offered as supported in the current profile. Separate runtime/API contract; complete coverage pending

requestAnimationFrameUI · AttarPartial support

Native frame callbacks exist; CSS animation progress is a separate capability.

Assessment: 2026-09-13
Runtime CSS rule generationDesign · AttarNot planned

New rules at runtime excluded; planned Blink-native value updates are separate

Assessment: 2026-09-12

Excluded by an accepted design decision; this is not an implementation backlog item.

Runtime failure / teardownBuild & tools · Attar ElectronSupported

Eight main failure phases checked with doubles

Assessment: 2026-09-12
safeStorageElectron APIs · Attar ElectronPartial support

OS secret-store interface; product proof pending

Assessment: 2026-09-12
screenElectron APIs · Attar ElectronPartial support

Display facade; complete display/event coverage pending

Assessment: 2026-09-12
scrollIntoView()UI · AttarPartial support

Boolean alignment is admitted. The options-object form is rejected.

Assessment: 2026-09-13
ServiceWorkerMainElectron APIs · Attar ElectronNot supported

Not offered as supported in the current profile. Upstream loader present; worker runtime unverified

Assessment: 2026-09-12
sessionElectron APIs · Attar ElectronPartial support

Partition facade; Cookies/WebRequest/storage parity pending

Assessment: 2026-09-12
setTimeout / setIntervalUI · AttarSupported

setTimeout and setInterval run in the UI runtime; the certified app uses them (source selection, API polling) and passed its journeys. Scheduling under long main-worker turns is still being proven.

Assessment: 2026-09-16
shadcn/ui componentsReact · AttarPartial support

Fifteen unchanged shadcn components build and package as a standalone app. Of 20 checked scenarios 9 pass: startup, five mounts and three interaction and unmount runs; the rest fail on missing DOM APIs. The target catalogue is 63 components.

Assessment: 2026-09-16
ShareMenuElectron APIs · Attar ElectronNot supported

Not offered as supported in the current profile. Source present; native sharing path unverified

Assessment: 2026-09-12
shellElectron APIs · Attar ElectronPartial support

openExternal slice; other OS operations have gaps

Assessment: 2026-09-12
sqliteNode.js · Attar ElectronNot supported

Not offered as supported in the current profile. No Attar Node SQLite result catalogued

Standalone UI bundlingBuild & tools · AttarSupported

UI graphs build with no Electron facade and no main process; the standalone examples go from that bundle to a packaged app.

Assessment: 2026-09-16
Static stylesheetsUI · AttarSupported

The app's static CSS files are parsed once by Blink, which owns cascade, layout and paint; measured on the certified Etcher stylesheet (flex, sticky, transforms, gradients, font-face) with 16 screens at pixel parity against Electron.

Assessment: 2026-09-16
Stock Electron / Node runtime payloadDesign · Attar ElectronNot planned

Whole runtime payload excluded; reusable upstream sources remain admitted

Assessment: 2026-09-12

Excluded by an accepted design decision; this is not an implementation backlog item.

streamNode.js · Attar ElectronPartial support

Pinned JS; native/async dependency closure pending

stream/consumersNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

stream/promisesNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

stream/webNode.js · Attar ElectronPartial support

Web stream source/bindings; full parity unverified

string_decoderNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

SVGUI · AttarSupported

Inline SVG and SVG as image render through Blink's own SVG path: 39 of 39 corpus items match stock Chromium's pixel counts, and the logo journeys (valid and malformed) are equivalent to Electron.

Assessment: 2026-09-16
Synchronous renderer IPCBuild & tools · Attar ElectronNot planned

Renderer sync IPC rejected by the accepted execution design

Assessment: 2026-09-12

Excluded by an accepted design decision; this is not an implementation backlog item.

sysNode.js · Attar ElectronNot supported

Not offered as supported in the current profile. Full module behavior not certified; provider coverage pending

systemPreferencesElectron APIs · Attar ElectronPartial support

Appearance slice; full OS API coverage pending

Assessment: 2026-09-12
testNode.js · Attar ElectronNot supported

Not offered as supported in the current profile. Full module behavior not certified; provider coverage pending

test/reportersNode.js · Attar ElectronNot supported

Not offered as supported in the current profile. Full module behavior not certified; provider coverage pending

Text input and IMEUI · AttarSupported

Keyboard input, key repeat, caret, selection, undo and IME composition are in the profile; in the human pass an Option+e dead key composed and committed in a URL field through the HID tap.

Assessment: 2026-09-16
timersNode.js · Attar ElectronPartial support

Engine probe exists; current product not proven

timers/promisesNode.js · Attar ElectronPartial support

Pinned source; cancellation/context parity pending

tlsNode.js · Attar ElectronPartial support

Pinned JS; certificate/transport provider closure pending

TouchBarElectron APIs · Attar ElectronNot supported

Not offered as supported in the current profile. Source present; native control support unverified

Assessment: 2026-09-12
trace_eventsNode.js · Attar ElectronNot supported

Not offered as supported in the current profile. Full module behavior not certified; provider coverage pending

TrayElectron APIs · Attar ElectronNot supported

native provider missing

Assessment: 2026-09-12
TreeWalker and NodeFilterWeb APIs · AttarPartial support

Blink owns traversal, currentNode and filter rejection; JavaScript projects the callback and node identity. Native bridge tests cover directions, filter reentry and teardown.

Assessment: 2026-09-16
ttyNode.js · Attar ElectronPartial support

Native fixture evidence; product parity pending

Typed arrays / ArrayBufferJavaScript · Attar AOTPartial support

Fixed-length ArrayBuffer, TypedArray and DataView: 86 % of TypedArray files and 69 % of ArrayBuffer files pass Test262; slice, with, toSorted and detach semantics have failures. Resizable buffers are an accepted boundary.

Assessment: 2026-09-16
Typed capabilitiesBuild & tools · AttarSupported

Twenty typed capabilities are in the current profile, each with its own fixture: fetch, WebSocket, URL, crypto.random, localStorage, user-selected file reads, dialogs, notifications, open external, window, update. Admission of an API does not make its provider complete.

Assessment: 2026-09-16
TypeScript and JSX / TSXBuild & tools · AttarSupported

TypeScript and TSX are the input language: the certified Etcher port and both standalone examples are TSX compiled ahead of time.

Assessment: 2026-09-16
Unknown runtime executable importsDesign · Attar AOTNot planned

New executable graph at runtime excluded; finite precompiled module choices are separate

Assessment: 2026-09-12

Excluded by an accepted design decision; this is not an implementation backlog item.

URL APINode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

utilNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

util/typesNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

utilityProcessElectron APIs · Attar ElectronNot supported

native provider missing

Assessment: 2026-09-12
v8Node.js · Attar ElectronPartial support

Named adapter surface; V8-specific behavior unavailable

V8 runtime / V8 browser bindingsDesign · Attar AOTNot planned

Excluded from the native product; compatible helper APIs do not embed V8

Assessment: 2026-09-12

Excluded by an accepted design decision; this is not an implementation backlog item.

ViewElectron APIs · Attar ElectronNot supported

native provider missing

Assessment: 2026-09-12
vmNode.js · Attar ElectronNot supported

Named adapter; arbitrary evaluation/contexts unavailable

wasiNode.js · Attar ElectronNot supported

No admitted WASI execution profile

Web Crypto APINode.js · Attar ElectronNot supported

Complete Node Web Crypto backend not established

Web fontsUI · AttarSupported

@font-face from bundled files and system fallback are in the profile; the certified app ships two TTF faces and its text matched the Electron reference at pixel parity.

Assessment: 2026-09-16
Web Streams APINode.js · Attar ElectronPartial support

Scoped host/engine adapters; complete Node parity pending

webContentsElectron APIs · Attar ElectronPartial support

Single-window facade; navigation/printing/DevTools gaps

Assessment: 2026-09-12
WebContentsViewElectron APIs · Attar ElectronNot supported

native provider missing

Assessment: 2026-09-12
webFrameElectron APIs · Attar ElectronPartial support

Frame facade; complete Blink/engine binding unverified

Assessment: 2026-09-12
webFrameMainElectron APIs · Attar ElectronPartial support

Frame identity slice; full lifecycle proof pending

Assessment: 2026-09-12
webUtilsElectron APIs · Attar ElectronNot supported

native provider missing

Assessment: 2026-09-12
Windows packagesBuild & tools · AttarNot supported

Windows is a planned target; a build for it ends with the stable error CP0003_UNSUPPORTED_TARGET.

Assessment: 2026-09-16
worker_threadsNode.js · Attar ElectronNot supported

Source imported; worker execution not established

zlibNode.js · Attar ElectronPartial support

Full module behavior not certified; provider coverage pending

Upstream internals and alternative integration APIs

Kept for completeness. These entries are not part of the feature count.

C++ embedder APINode.js · Attar ElectronNot supported

Node embedding API; Attar/AOT supply different embedding

IpcMainServiceWorkerElectron APIs · Attar ElectronNot supported

Declaration only; no runtime export at this pin

Assessment: 2026-09-12
seaNode.js · Attar ElectronNot supported

Node executable format; Attar has its own packaging

What the map does not say

Assessments, not a release verdict.

Every state comes from an Attar team assessment of the implementation and its checks. The underlying Electron, Node and browser inventory is dated 2026-09-12; the platform entries and specific updates are dated .

Never counts as supported
  • Upstream source in the tree, on its own.
  • A passing fixture, as a current packaged result.
  • A different feature that happens to work nearby.
Where the rest lives
  • The data behind this page, every feature ID included: features.json.
  • Upstream references describe third-party APIs. Attar is not open source; they do not link to its implementation.
  • Not planned always cites an accepted design decision in the note's scope.
  • Measured runs of Test262 and Web Platform Tests are on the compliance page.