Capabilities

Which high-level features a Program can actually use when it renders to JavaScript for the browser.

How a Program becomes JavaScript, in parts. Start with the introduction, then follow each part into the rendered output and the runtime it links against.

Introduction — what the JavaScript target is, and how to read the rest of this section.
Capabilities — which high-level features are possible, built in or through a library.
Coding standards — the Frenzi coding standards the generated code follows, global and JavaScript-specific.
Example — a full program using every keyword, and the JavaScript it renders to.
Naming considerations — how Program's dotted names are carried into JavaScript.
Entry point — the generated main() that wires up the drivers and starts the reactive cycle.
Drivers — the native drivers that provide capabilities like the user interface and animation, draining each cycle's emissions.
Runtime — the Reactive and Context machinery the rendered code links against.
Native modules — the hand-written, per-platform JavaScript behind NATIVE functions.
Keywords — how each of Program's keywords renders to JavaScript.
Project setup — the files and commands to build and run the rendered program.
Reserved words — the words JavaScript keeps for itself, and how a Program name that collides with one is escaped.

What the browser can do

JavaScript for the browser is a rich, mature platform. The reactive core is host-agnostic; the drivers decide what a program can reach, and in the browser almost everything is available — usually built in.

Feature	Status	How
User interface	Built in	The DOM interface driver renders Ui straight into the page; custom components wrap any DOM widget or library.
Networking	Built in	Network uses the platform `fetch` and `WebSocket`; no dependency.
Asynchrony	Built in	A LOCKED state models an in-flight value; the driver resolves it on a microtask and re-enters the cycle. No `async`/`await` in Program.
Animation	Built in	The Animate driver shares one `requestAnimationFrame` ticker.
Storage	Built in	Storage maps to `localStorage` / IndexedDB; file open and save go through the browser's picker and download.
Graphics	Built in	Canvas and WebGL are reachable through a custom interface component or a Graphics driver.
Location	Via the platform	Location uses the Geolocation API; a map is a custom component backed by a mapping library.
Background threads	Limited	The reactive cycle is single-threaded and cooperative. Heavy work can be pushed to a Web Worker behind a native module, but shared reactive state does not cross the boundary.
Local filesystem	Not directly	The browser sandbox has no arbitrary file access; only the user-driven file picker and downloads. A server or the Node build is needed for real files.

Where a capability needs host code, it arrives as a NATIVE function or a driver — see native modules and drivers.

Capabilities

Contents

What the browser can do