- server.close() closes idle keep-alive connections, and every open
connection closes after keepAliveTimeout + keepAliveTimeoutBuffer, so a
closed server whose clients keep their connections no longer stays up.
The Keep-Alive response header gives keepAliveTimeout in whole seconds
and is omitted when it is 0.
- A client request through an Agent with neither keepAlive nor a finite
maxSockets sends Connection: close.
- "socket hang up" and "aborted" errors carry code ECONNRESET, a client
head over the header limit fails with HPE_HEADER_OVERFLOW, and TLS
verification failures carry their openssl code.
- Outgoing header values keep the type they were set with: getHeader and
getHeaders answer numbers and arrays, appendHeader turns an existing
value into an array, and setHeader(name, string[]) writes one line per
element.
- Repeated incoming header fields join with ", " ("; " for cookie),
Node's single-value fields keep the first value, and set-cookie reads
as an array under @types/node, on server requests and client responses.
Fetch reads response headers line by line.
- Expect: 100-continue is answered with 100 Continue before 'request';
other expectations answer 417.
- HEAD requests and 1xx/204/304 responses send no body or length header,
and HTTP/1.0 requests without a set length get an unframed body and
Connection: close.
- The 16 KiB maxHeaderSize applies to the request target plus header
names and values (431 on the server).
- https.Agent TLS options are refused by name instead of being dropped,
and server.address() lowers for @types/node's
string | AddressInfo | null result.
Corpus 5555-5563 and the node-types http-headers-address fixture cover
each case.
scriptc
scriptc compiles TypeScript and JavaScript to native executables and WebAssembly. It uses the types checked by the TypeScript compiler to generate machine code, and the output runs without Node.js installed. npm packages your program imports compile along with it. Code scriptc can't compile is reported at build time with a diagnostic and, where available, a rewrite hint.
scriptc is experimental and supports a subset of JavaScript, TypeScript, and Node.js APIs. Run scriptc coverage on an existing program to see how much of it compiles, and see the limitations and Node.js compatibility reference for details.
Installation
Install with Node.js 24 or later and npm:
$ npm install -g scriptc
The installed compiler runs natively on macOS, Linux, and Windows. Node.js is needed only to install it and to run WASI modules with scriptc run. Standalone compiler archives are also available from GitHub Releases.
Building executables requires a linker and the platform SDK or sysroot. See the quickstart for prerequisites and platform support for host requirements, cross-compilation, and WebAssembly.
Build a program
Create hello.ts:
const who = process.argv.length > 2 ? process.argv[2] : "world";
console.log(`hello, ${who}`);
scriptc run compiles the file and runs the result:
$ scriptc run hello.ts
hello, world
scriptc build writes an executable:
$ scriptc build hello.ts -o hello >/dev/null
$ ./hello scriptc
hello, scriptc
These examples use POSIX shell syntax. On Windows, build hello.exe and run it with .\hello.exe.
Use scriptc coverage hello.ts to check what compiles before you build. See coverage reports for details.
Use Node APIs
Supported Node APIs compile to the native runtime. For example, server.ts:
import { createServer } from "node:http";
const server = createServer((req, res) => {
res.setHeader("content-type", "application/json");
res.end(JSON.stringify({ path: req.url }));
});
server.listen(8080, () => {
console.log("listening on http://localhost:8080");
});
$ scriptc build server.ts -o server >/dev/null
$ ./server
listening on http://localhost:8080
Use npm packages
npm packages compile into the executable with your code, so it doesn't read node_modules at runtime.
Create cli.ts:
import pc from "picocolors";
console.log(pc.green("hello from scriptc"));
$ npm install picocolors
$ scriptc build cli.ts -o cli >/dev/null
$ ./cli
hello from scriptc
Package support is partial. See npm dependencies for which packages compile and how to check them.
Documentation
- Introduction: what scriptc is and what you can build.
- Quickstart: installation and your first executable.
- Coverage reports: check whether an existing program compiles.
- Platform support: cross-compilation and WebAssembly.
- CLI reference: commands, options, and output formats.
- Native program objects: use compiler output in external builds.
- Native FFI: call C ABI functions from compiled programs.
- WebAssembly modules: build and embed WASI modules.
- Examples: programs and integration examples in this repository.
Contributing
See CONTRIBUTING.md for source setup, testing, native artifact builds, and docs development.