TypeScript Native Compiler

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A native ahead-of-time (AOT) and JIT compiler for TypeScript, built on LLVM/MLIR. It compiles .ts files directly to native executables, WebAssembly, or runs them on the fly via a built-in JIT — no Node.js or JavaScript runtime required.

CI Status

Contents

• What's new
• Roadmap
• Demo
• Try it online
• Example
• Running your code
  • As JIT
  • As a native executable
  • As WebAssembly
• Building from source
• Community
• License

What's new

• Implemented try/catch exception handling in the JIT on Windows (x64 SEH unwinding via a custom LLJIT runtime)

• Migrared to LLVM 22.1.8

• Migrated to Visual Studio 2026 (Windows build chain)

• JavaScript Built-in objects library [Default Library repo]

• Visual Studio Code project

tslang --new Test1

• CMake project (mixed C++/TypeScript, TSLANG registered as a first-class CMake language)

tslang --cmake Test1

Generates a ready-to-build project (CMakeLists.txt, CMakePresets.json, main.cpp, sample .ts sources and the cmake/ TSLANG language modules). Build it with:

cd Test1
cmake --preset default && cmake --build --preset default

• Strict null checks

let sn: string | null = null; // Ok
let s: string = null; // error

• Improved Template Literal Types

type Color = "red" | "green" | "blue";
type HexColor<T extends Color> = `#${string}`;

• Public, private, and protected modifiers

class Point {
    private x: number;
    #y: number;
}

const p = new Point();
p.x // access error
p.#y // error

• Class from Tuple

class Point {
    x: number;
    y: number;
}

class Line {
    constructor(public start: Point, public end: Point) { }
}

const l = new Line({ x: 0, y: 1 }, { x: 1.0, y: 2.0 });

• Compile-time ifs

function isArray<T extends unknown[]>(value: T): value is T {
    return true;
}

function gen<T>(t: T)
{
    if (isArray(t))
    {
        return t.length.toString();
    }

    return "int";
}

const v1 = gen<i32>(23); // result: int
const v2 = gen<string[]>([]); // result: 0

• Migrated to LLVM 19.1.3

• Improved generating debug information — more info here: Wiki:How-To

tslang --di --opt_level=0 --emit=exe example.ts

• More What's New entries on the wiki

Roadmap

• Migrating to LLVM 22.1.8
• Shared libraries
• JavaScript Built-in classes library

Demo

See the release page for a recorded demo

Try it

Open the WASM example on Compiler Explorer

Chat Room

Want to chat with other members of the TypeScriptCompiler community?

• GitHub Discussions (preferred)
• (legacy)

Example

abstract class Department {
    constructor(public name: string) {}

    printName(): void {
        print("Department name: " + this.name);
    }

    abstract printMeeting(): void; // must be implemented in derived classes
}

class AccountingDepartment extends Department {
    constructor() {
        super("Accounting and Auditing"); // constructors in derived classes must call super()
    }

    printMeeting(): void {
        print("The Accounting Department meets each Monday at 10am.");
    }

    generateReports(): void {
        print("Generating accounting reports...");
    }
}

function main() {
    let department: Department; // ok to create a reference to an abstract type
    department = new AccountingDepartment(); // ok to create and assign a non-abstract subclass
    department.printName();
    department.printMeeting();
    //department.generateReports(); // error: department is not of type AccountingDepartment, cannot access generateReports
}

Run

tslang --emit=jit --opt --shared-libs=TypeScriptRuntime.dll example.ts

Result

Department name: Accounting and Auditing
The Accounting Department meets each Monday at 10am.

Run as JIT

File hello.ts

function main() {
    print("Hello World!");
}

Build

tslang hello.ts

Result

Hello World!

Compile as Binary Executable

Make sure you have download tslang from releases first.

The compile process may use a few environment variables so the linker can find the runtime libraries, then invoke tslang with --emit=exe. Edit the paths to match your checkout — the C:\dev\... / ~/dev/... values are only examples.

Variable	Points to
GC_LIB_PATH	Boehm GC library (the garbage collector)
LLVM_LIB_PATH	LLVM/MLIR libraries
TSLANG_LIB_PATH	TSLANG runtime library
DEFAULT_LIB_PATH	Default library

Compile on Windows

Build

tslang --emit=exe hello.ts

Run

hello.exe

Result

Hello World!

Compile on Linux (Ubuntu 20.04 and 22.04)

Build

./tslang --emit=exe hello.ts --relocation-model=pic

Run

./hello

Result

Hello World!

Compiling as WASM

WASM build on Windows

Build

tslang.exe --emit=exe --nogc -mtriple=wasm32-unknown-unknown hello.ts

Run run.html

Click to expand the full run.html WebAssembly loader

<!DOCTYPE html>
<html>

<head></head>

<body>
    <script type="module">
        let buffer;
        let buffer32;
        let buffer64;
        let bufferF64;
        let heap;

        let heap_base, heap_end, stack_low, stack_high;

        const allocated = [];

        const allocatedSize = (addr) => {
            return allocated["" + addr];
        };

        const setAllocatedSize = (addr, newSize) => {
            allocated["" + addr] = newSize;
        };

        const expand = (addr, newSize) => {

            const aligned_newSize = newSize + (4 - (newSize % 4))

            const end = addr + allocatedSize(addr);
            const newEnd = addr + aligned_newSize;

            for (const allocatedAddr in allocated) {
                const beginAllocatedAddr = parseInt(allocatedAddr);
                const endAllocatedAddr = beginAllocatedAddr + allocated[allocatedAddr];
                if (beginAllocatedAddr != addr && addr < endAllocatedAddr && newEnd > beginAllocatedAddr) {
                    return false;
                }
            }

            setAllocatedSize(addr, aligned_newSize);
            if (addr + aligned_newSize > heap) heap = addr + aligned_newSize;
            return true;
        };

        const endOf = (addr) => { while (buffer[addr] != 0) { addr++; if (addr > heap_end) throw "out of memory boundary"; }; return addr; };
        const strOf = (addr) => String.fromCharCode(...buffer.slice(addr, endOf(addr)));
        const copyStr = (dst, src) => { while (buffer[src] != 0) buffer[dst++] = buffer[src++]; buffer[dst] = 0; return dst; };
        const ncopy = (dst, src, count) => { while (count-- > 0) buffer[dst++] = buffer[src++]; return dst; };
        const append = (dst, src) => copyStr(endOf(dst), src);
        const cmp = (addrL, addrR) => { while (buffer[addrL] != 0) { if (buffer[addrL] != buffer[addrR]) break; addrL++; addrR++; } return buffer[addrL] - buffer[addrR]; };
        const prn = (str, addr) => { for (let i = 0; i < str.length; i++) buffer[addr++] = str.charCodeAt(i); buffer[addr] = 0; return addr; };
        const clear = (addr, size, val) => { for (let i = 0; i < size; i++) buffer[addr++] = val; };
        const aligned_alloc = (size) => { 
            const aligned_size = size + (4 - (size % 4)); 
            if ((heap + aligned_size) > heap_end) throw "out of memory"; 
            setAllocatedSize(heap, aligned_size); 
            const heapCurrent = heap; 
            heap += aligned_size; 
            return heapCurrent; 
        };
        const free = (addr) => delete allocated["" + addr];
        const realloc = (addr, size) => {
            if (!expand(addr, size)) {
                const newAddr = aligned_alloc(size);
                ncopy(newAddr, addr, allocatedSize(addr));
                free(addr);
                return newAddr;
            }

            return addr;
        }

        const envObj = {
            memory: new WebAssembly.Memory({ initial: 256 }),
            table: new WebAssembly.Table({
                initial: 0,
                element: 'anyfunc',
            }),
            fmod: (arg1, arg2) => arg1 % arg2,
            sqrt: (arg1) => Math.sqrt(arg1),
            floor: (arg1) => Math.floor(arg1),
            pow: (arg1, arg2) => Math.pow(arg1, arg2),
            fabs: (arg1) => Math.abs(arg1),
            _assert: (msg, file, line) => console.assert(false, strOf(msg), "| file:", strOf(file), "| line:", line, " DBG:", path),
            puts: (arg) => output += strOf(arg) + '\n',
            strcpy: copyStr,
            strcat: append,
            strcmp: cmp,
            strlen: (addr) => endOf(addr) - addr,
            malloc: aligned_alloc,
            realloc: realloc,
            free: free,
            memset: (addr, size, val) => clear(addr, size, val),
            atoi: (addr, rdx) => parseInt(strOf(addr), rdx),
            atof: (addr) => parseFloat(strOf(addr)),
            sprintf_s: (addr, sizeOfBuffer, format, ...args) => {
                const formatStr = strOf(format);
                switch (formatStr) {
                    case "%d": prn(buffer32[args[0] >> 2].toString(), addr); break;
                    case "%g": prn(bufferF64[args[0] >> 3].toString(), addr); break;
                    case "%llu": prn(buffer64[args[0] >> 3].toString(), addr); break;
                    default: throw "not implemented"; 
                }

                return 0;
            },
        }

        const config = {
            env: envObj,
        };

        WebAssembly.instantiateStreaming(fetch("./hello.wasm"), config)
            .then(results => {
                const { main, __wasm_call_ctors, __heap_base, __heap_end, __stack_low, __stack_high } = results.instance.exports;
                buffer = new Uint8Array(results.instance.exports.memory.buffer);
                buffer32 = new Uint32Array(results.instance.exports.memory.buffer);
                buffer64 = new BigUint64Array(results.instance.exports.memory.buffer);
                bufferF64 = new Float64Array(results.instance.exports.memory.buffer);
                heap = heap_base = __heap_base, heap_end = __heap_end, stack_low = __stack_low, stack_high = __stack_high;
                try
                {
                    if (__wasm_call_ctors) __wasm_call_ctors();
                    main();
                }
                catch (e)
                {
                    console.error(e);
                }
            });
    </script>
</body>

</html>

Build

Build on Windows

Windows Requirements

• Visual Studio 2026
• ~50 GB of free disk space (LLVM/MLIR build dominates this)

The hardcoded C:\dev\... paths in the scripts below are examples — adjust them to your checkout location.

First, precompile dependencies

cd TypeScriptCompiler
prepare_3rdParty.bat

To build TSLANG binaries:

cd TypeScriptCompiler\tslang
config_tslang_release.bat
build_tslang_release.bat

Build on Linux (Ubuntu 20.04 and 22.04)

Linux Requirements

• gcc or clang
• cmake
• ninja-build
• ~50 GB of free disk space (LLVM/MLIR build dominates this)
• sudo apt-get install libtinfo-dev

First, precompile dependencies

chmod +x *.sh
cd ~/TypeScriptCompiler
./prepare_3rdParty.sh

To build TSLANG binaries:

cd ~/TypeScriptCompiler/tslang
chmod +x *.sh
./config_tslang_release.sh
./build_tslang_release.sh

License

This project is licensed under the MIT License — see the LICENSE file for details.

Contributing

Issues and pull requests are welcome. See the Wiki for documentation, build notes, and how-to guides.