Vercel releases Scriptc, a TypeScript-to-native compiler without a JavaScript engine

Introducing Scriptc for Native TypeScript

Vercel has launched Scriptc, a new compiler designed to transform TypeScript code into native executables. This tool allows developers to create applications that run without requiring a Node.js runtime or a V8 JavaScript engine embedded in the binary. The resulting executables are self-contained and feature fast startup times, as demonstrated by a 178KB binary with a ~2ms startup time for a Fibonacci calculation example.

Compilation Process and Compatibility

Scriptc processes standard TypeScript code without requiring any modifications, annotations, or dialect changes. It uses the real TypeScript compiler for type-checking and aims for byte-for-byte behavioral compatibility with Node.js execution. The primary development platform is macOS arm64, with support for Linux and Windows through cross-compilation, verified by differential testing.

Static and Dynamic Execution Tiers

Scriptc analyzes TypeScript constructs to determine what can be compiled to native code. It operates on three tiers: statically compiled native code (the default), dynamically run code using an embedded QuickJS-ng engine (for elements like npm dependencies or 'any'-typed code), and rejected code that fails with specific error messages and rewrite hints. The static compilation covers a significant portion of the language and standard library, including classes, closures, generics, async/await, and regular expressions.

Impact on TypeScript Development

The introduction of Scriptc could broaden the applicability of TypeScript, enabling its use in scenarios where minimal overhead and fast execution are critical, such as command-line tools, embedded systems, or serverless functions with strict cold-start requirements. By removing the dependency on a full JavaScript runtime, Scriptc offers a path to more efficient and performant TypeScript applications.