Installation

There is no download yet. No prebuilt binary is published anywhere for nstd, and nothing in this project's CI builds or releases one. The nstdlib library published on npm is not the same thing as this binary. Today, building from source is the only way to get nstd.

#Prerequisites

• Zig 0.16.0. This is a hard requirement, pinned in the build config, not just a recommendation.
• Node.js, matching the version in this repository's .nvmrc (currently 26.7.0). The build reads information out of the exact Node version it runs under to generate parts of the standard library, so a mismatched Node produces a broken build. If your default node is a different version, install a matching one and use that.
• pnpm, via Corepack. corepack enable is enough if you don't already have it.
• Git, with the ability to fetch this repository's submodule (a pinned checkout of Node's own source, which the build reads from).

#Build from source

Clone the repository and fetch its submodule:

git clone https://github.com/unjs/nstd.git
cd nstd
git submodule update --init --depth 1

Install dependencies:

corepack enable
pnpm install

Build nstdlib itself first. This produces ./dist, the standard library that gets embedded into the binary:

pnpm build

Then build the native runtime:

pnpm --filter nstdlib-native build

This stages ./dist into native/assets/, then runs a Zig release build. The finished binary lands at native/zig-out/bin/nstd. Plain zig build with no flags produces an unoptimized debug binary instead, so use the pnpm script above rather than calling Zig directly, unless you specifically want a debug build to chase down a Zig-level crash.

#Check it worked

./native/zig-out/bin/nstd -e 'console.log(1 + 1)'
./native/zig-out/bin/nstd --print-realm

The first line should print 2. --print-realm prints how many of Node's builtin modules (fs, http, path, and so on) registered successfully in this build; it should report every one of them available and none missing.

From here, try running a real script:

./native/zig-out/bin/nstd my-script.js

#Building for wasm32-wasi

A WASI build is real and produces a working binary, booting the same standard library as the native build:

pnpm --filter nstdlib-native build:wasm

This produces native/zig-out/bin/nstd.wasm, which runs under any WASI-compatible runtime, for example wasmtime:

wasmtime native/zig-out/bin/nstd.wasm -- --print-realm

Two things are missing from this build. Networking is unavailable on every wasm target, so net, http and fetch answer ENOSYS rather than opening a connection, and fs.watch() needs inotify, so it is refused by name. Everything else boots the same as the native build.

This target is also a step toward running nstd inside a browser, though not the final form of that: three pieces (exiting the process, the wait the event loop does, and file access) still assume a WASI-style host and would need to be swapped out.

#Next

Once you have a working binary, Running Code covers actually using it, and CLI Options documents the flags it accepts.