No runtime, no VM
The output is a native executable from clang -O2, not a bundled interpreter. Zero startup warmup, small binaries, plain libc by default.
TypeScript · LLVM · clang -O2 TypeScript,
TypeScript,
compiled
to native.
You write .ts. It writes LLVM IR, hands it to clang, and out comes a real executable. Your operating system is none the wiser. No runtime. No V8. No Electron.
Single-developer, experimental, AGPL-3.0. Built for CLI tools & Docker microservices.
$ git clone https://github.com/memphisx/KlainMainLang
$ cd KlainMainLang && make build # → ./klainmain
$ ./klainmain app.ts # → native binary
$ ./app
hello, native worldTargeted feature areas
~95%TypeScript core language295 / 309 targeted features
100%Web Platform APIs55 / 55 targeted features
~95%Node.js APIs81 / 85 targeted features
These are curated feature-area checklists, “does the core case work?”, not external conformance. They mirror the project's own status matrix, caveats and all.
External conformance · full public suites14.8%Test262 (in-scope subset)5,067 / 34,334 · 10.9% over the full corpus
51.4%TypeScript accept/reject4,755 / 9,256 cases agree with tsc
1.8%Node.js test/parallel21 / 1,195 runnable files pass
Low on purpose, and shown on purpose. This is a typed subset: most of Test262 is eval-based untyped JS, and Node's suite is dynamic JavaScript against the full platform. Both largely out of scope by design, not silent failures. The honest breakdown.
Why it exists
Real servers
http.listen speaks HTTP/1.1 and HTTP/2 (h2c) on one port. fs, worker_threads and cluster give you real OS threads and processes. TLS on both ends.
Browser-shaped APIs, off-browser
fetch, URL, WebSocket, Web Crypto, Streams, AbortController, timers, the web APIs that make sense without a DOM, and none of the ones that don't.
You pick the trade-offs
number is a JS-faithful 64-bit float by default, opt into sized machine ints (int8…uint64) with a JSDoc width when you want them. Memory is manual by default (never frees, perfect for short-lived CLIs); pass -mm=gc for a real Boehm collector. Crypto / bigint / regex backends chosen per compile.
Real TypeScript in,
real binaries out
Every snippet below is an actual file under examples/. It compiles and runs, verified on every build. No slideware.
import http from 'http'
interface Res {
status: number
body: string
headers: Map<string, string>
}
http.listen(8080, (req: HttpRequest): Res => {
let respHeaders: Map<string, string> = new Map<string, string>()
respHeaders.set('Content-Type', 'text/plain')
if (req.path === '/hello') {
let name: string = req.query.has('name') ? req.query.get('name') : 'stranger'
return { status: 200, body: 'hello, ' + name, headers: respHeaders }
}
return { status: 404, body: 'not found: ' + req.path, headers: respHeaders }
})The pipeline,
in one breath
- 01
Lexer
Source text becomes a flat token stream.
- 02
Parser
Recursive descent with Pratt precedence climbing builds the AST.
- 03
Resolver
Transitive imports are parsed and merged into one AST.
- 04
LLVM emitter
~60 small domain files write LLVM IR text.
- 05
clang -O2
The real backend turns IR into a host-arch binary.
→ one .ll, one clang call, one generated main(), one binary that runs unsupervised.
What actually works
Exact match to JS Works, with minor differences
Async / PromiseLanguage100%Classes / OOPLanguage100%Array methodsLanguage100%Number / MathLanguage100%Type primitivesLanguage100%Object & collectionsLanguage97%ModulesLanguage94%String methodsLanguage93%JSONLanguage87%Type system featuresLanguage82%Networking (fetch, WS, SSE)Web platform100%StreamsWeb platform100%Web CryptoWeb platform100%Workers / ConcurrencyWeb platform100%Binary data & Typed ArraysWeb platform100%URLWeb platform100%TimersWeb platform100%HTTP ServerNode.js100%events (EventEmitter)Node.js100%pathNode.js100%osNode.js100%File System (fs)Node.js93%Process / CLI I/ONode.js92%Other core modulesNode.js92%
Full status matrix
A bare : number is a JS-faithful 64-bit float. Reach for a JSDoc int8…uint64 width when you mean real integers. Memory is manual by default (-mm=gc for a collector). Concurrency is cooperative. Nothing is dynamic. All deliberate.
The name is the mission statement
KlainMain
Not German. Not a clothing brand. Klain Main isn't “klein Main” (a cute little main()), and it isn't the Augsburg streetwear label. It's Greek.
Κλάιν Μάιν is slang for “I don't care”, the good kind: do the thing anyway, even when everyone tells you it's futile, for no better reason than because you can. That's the whole reason this compiler exists, because “how would I even build one” turned out to be a far better rabbit hole than whatever the day's actual plan was.
Read the docs