Rust JavaScript surface

Select with surfaces: ["js"]. The target composes the shared JavaScript source profile and activates @tsonic/rust-js only when selected operations require it.

Implemented closed families include arrays, strings, maps, sets, dates, JSON with replacer callbacks and selected toJSON, regular expressions, promises, Intl, symbols, weak collections, timers, numeric/math operations, console APIs, object-shape operations, and numeric typed arrays covered by the operation inventory and runtime proofs.

const expression = /(?<name>[a-z]+)/giu;
const match = expression.exec("Tsonic");
console.log(match?.groups?.name);

Regular expressions use an ECMAScript engine rather than translating patterns to Rust regex syntax. Exact UTF-16 behavior uses the explicit JsString lane only where selected; native Rust strings remain the default carrier.

The JS surface does not add an embedded JavaScript engine or open reflection. Each accepted operation has one static Rust lowering or one closed runtime contract. Unsupported dynamic behavior rejects.

See the detailed support inventory.