Remote<T> and TypeScript

Remote<T> is the type of your value as the other side sees it: functions become async, containers map recursively, platform objects revive as themselves. At the expose() call site, a compile-time Capable check rejects values that can’t cross the wire.

The Remote<T> mapping

Local type	Remote type
(...args: P) => R	(...args: P) => Promise<Remote<Awaited<R>>>
Promise<U>	Promise<Remote<U>>
AsyncIterable<U>	AsyncIterableIterator<Remote<U>>
Map, Set, Date, Error, RegExp, ArrayBuffer, ArrayBufferView, ReadableStream, WritableStream, MessagePort, EventTarget, Request, Response, Headers, File, FileList	itself (clone transports only; Blob is not supported)
arrays / objects	mapped recursively
primitives	themselves

Generic signatures collapse

Mapped types cannot preserve type parameters, so a generic remote function loses its generics in Remote<T>.

The Capable compile-time check

expose() validates the value you pass at compile time against Capable, the union of everything serializable for the inferred transport. Failures pinpoint the offending path:

expose({ ok: async () => 1, cache: new WeakMap() }, { transport: worker })
// type error: Value type must resolve to a Capable, with `cache` identified as the bad field

The error identifies the offending path and its parent object, so a WeakMap buried three levels deep fails at compile time, not at runtime. (At runtime, unclonables coerce to {} — see limitations.)

Registering custom revivables widens the check: passing the extended module list type as the second type parameter of expose() teaches Capable that your type is now a legal value.

JSON transports narrow Capable

Capable is narrower on JSON transports: values that depend on structured clone (RegExp, SharedArrayBuffer, ImageBitmap, …) are rejected at the type level, so misuse fails at compile time rather than silently coercing. Everything with a dedicated revivable module (Date, Map, ArrayBuffer via base64, functions, streams, …) still works — see supported types for the full matrix.

Requirements

The package is strict-mode; the published declarations require TypeScript ≥ 5.9 with strict mode.