LambdaJS

LambdaJS is Lambda's built-in JavaScript JIT and browser DOM engine (~18K LOC). It transpiles JavaScript source code into MIR IR which is then compiled to native machine code, enabling near-native execution of JavaScript programs within the Lambda runtime.

Status: Experimental. LambdaJS passes 60/60 JS baseline tests (677/677 total) and runs all 53/53 benchmarks across 5 suites. It covers ES6 classes, prototype-based OOP, closures, typed arrays, template literals, try/catch/finally, destructuring, regex via RE2, optional chaining, Map/Set collections, and error subclasses. 5-suite geometric mean: 2.2× vs Node.js (V8) (JetStream standalone: 6.3×).

Usage

./lambda.exe script.js              # Run a JavaScript file with LambdaJS JIT

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Supported JavaScript Features

Language Syntax

Feature	Status	Notes
Variable declarations (var, let, const)	✅	Hoisting for var; block scoping for let/const
Function declarations & expressions	✅	Including hoisting
Arrow functions	✅	Lexical this
Template literals	✅	Backtick strings with ${expr} interpolation
Spread operator (...)	✅	In function calls and array literals
Rest parameters (...args)	✅
Default parameters	✅
Destructuring — arrays	✅	const [a, b] = arr
Destructuring — objects	✅	const {x, y} = obj, rename {x: px}, for-of
Destructuring — rest (...rest)	✅	Object rest {a, ...rest} and array rest [a, ...rest]
ES6 classes	✅	class, extends, super(), static, getters/setters
Prototype-based OOP	✅	Foo.prototype.method = fn, new Foo()
Closures	✅	Multi-level transitive capture, shared scope env
typeof operator	✅	All JS quirks (null → "object")
instanceof operator	✅
in operator	✅
delete operator	✅	Sets property to null (simplified)
Nullish coalescing (??)	✅
Conditional (ternary) ? :	✅
switch / case	✅	With fallthrough support
for...of	✅
for...in	✅
do...while	✅
try / catch / finally	✅	Including return-in-try
throw	✅
IIFE (function(){...})()	✅
Regex literals	✅	Via RE2 backend; .test(), .exec()
Sequence expressions (comma)	✅
Labeled statements	✅	break label, continue label
Nullish/logical assignment (??=, &&=, ||=)	✅
Optional chaining (?.)	✅	Property, method, computed, nested chains
Map / Set collections	✅	new Map(), new Set() with full method API
Generators / yield	❌
async / await / Promise	❌
import / export (ES modules)	❌
WeakMap / WeakSet	❌
Symbol API	✅	Symbol(), Symbol.for(), Symbol.keyFor(), well-known symbols
Proxy / Reflect	❌
setTimeout / setInterval	❌
encodeURIComponent / decodeURIComponent	✅	RFC 3986 percent-encoding via lib/url.c
structuredClone	❌
globalThis	✅	Singleton global object with undefined, NaN, Infinity
Intl	❌

Operators

Category	Operators	Status
Arithmetic	+, -, *, /, %, **	✅
Comparison	==, !=, ===, !==, <, <=, >, >=	✅
Logical	&&, ||, !	✅
Bitwise	&, |, ^, ~, <<, >>, >>>	✅
Unary	+x, -x, ++, --, typeof, void, delete	✅
Assignment	=, +=, -=, *=, /=, %=, **=, &=, |=, ^=, <<=, >>=, >>>=	✅

DOM Bridge

LambdaJS includes a DOM bridge for use with the Radiant layout engine:

Document Methods

Method	Status	Notes
getElementById	✅
getElementsByClassName	✅
getElementsByTagName	✅
querySelector	✅
querySelectorAll	✅
createElement	✅
createTextNode	✅
createElementNS	✅	Namespace ignored, delegates to createElement
write / writeln	✅	Simplified; appends text to body
normalize	✅	Merges adjacent text nodes at root
createDocumentFragment	✅	Lightweight container; children transfer on append
createComment	✅	Creates comment DOM node
importNode	✅	Deep clone from external tree
adoptNode	✅	Detaches node from current parent

Document Properties

Property	Status	Notes
body	✅
documentElement	✅
head	✅
title	✅
cookie	❌
readyState	❌
URL / location	✅	URL returns href string; location object with .href, .hostname, .pathname, etc.

Element Properties

Property	Status	Notes
tagName	✅
id	✅
className	✅
textContent	✅
children	✅
parentElement	✅
parentNode	✅
firstChild	✅
lastChild	✅
nextSibling	✅
previousSibling	✅
childNodes	✅
childElementCount	✅
nodeType	✅
nodeName	✅	Tag name or "#text"
nodeValue	✅	Alias for text node .data
firstElementChild	✅	Skips text nodes
lastElementChild	✅	Skips text nodes
nextElementSibling	✅	Skips text nodes
previousElementSibling	✅	Skips text nodes
innerHTML	✅	Getter and setter; setter parses HTML fragment
offsetWidth	✅	Returns 0 (JS runs before layout)
offsetHeight	✅	Returns 0 (JS runs before layout)
clientWidth	✅	Returns 0 (JS runs before layout)
clientHeight	✅	Returns 0 (JS runs before layout)
outerHTML	✅	Getter only
classList	✅	add, remove, toggle, contains, item, replace, length, value
dataset	✅	data-* attribute proxy with camelCase ↔ kebab-case conversion
scrollTop / scrollLeft	❌
getBoundingClientRect	❌

Element Methods

Method	Status	Notes
getAttribute	✅
setAttribute	✅
hasAttribute	✅
removeAttribute	✅
querySelector	✅
querySelectorAll	✅
matches	✅
closest	✅
appendChild	✅
removeChild	✅
insertBefore	✅
hasChildNodes	✅
cloneNode	✅
normalize	✅	Merges adjacent text nodes
replaceChild	✅
insertAdjacentHTML	✅	Parses HTML fragment at position
insertAdjacentElement	✅	Inserts element at position
remove	✅	Self-removal from parent
contains	✅	Subtree containment check
toggleAttribute	✅	Optional force parameter

Style

Feature	Status	Notes
element.style.prop get/set	✅	camelCase ↔ CSS conversion
getComputedStyle()	✅	Full cascade matching
element.style.cssText	✅	Getter only
element.style.setProperty()	✅	Sets inline style property
element.style.removeProperty()	✅	Removes inline style property

Built-in Objects & Methods

String Methods (24)

indexOf, lastIndexOf, includes, startsWith, endsWith, trim, trimStart, trimEnd, toLowerCase, toUpperCase, split, substring, slice, replace, replaceAll, charAt, charCodeAt, concat, repeat, padStart, padEnd, at, search, toString

Missing: match, matchAll, normalize, localeCompare, codePointAt

Array Methods (29)

push, pop, indexOf, lastIndexOf, includes, join, reverse, slice, concat, map, filter, reduce, reduceRight, forEach, find, findIndex, some, every, sort, flat, flatMap, fill, splice, shift, unshift, at, toString, from (static), isArray (static)

Missing: copyWithin, findLast, findLastIndex, toReversed, toSorted

Object Methods (13)

Object.keys, Object.values, Object.entries, Object.create, Object.defineProperty, Object.assign, Object.freeze, Object.isFrozen, Object.getPrototypeOf, Object.setPrototypeOf, Object.is, Object.fromEntries, hasOwnProperty

Missing: Object.seal, Object.getOwnPropertyNames

Math (27 methods + 8 constants)

Methods: abs, floor, ceil, round, sqrt, pow, min, max, log, log2, log10, exp, sin, cos, tan, asin, acos, atan, atan2, sign, trunc, random, cbrt, hypot, clz32, imul, fround

Constants: PI, E, LN2, LN10, LOG2E, LOG10E, SQRT2, SQRT1_2

Missing: sinh, cosh, tanh

Number (6 methods + 8 properties)

Methods: toFixed, toString, Number.isInteger, Number.isFinite, Number.isNaN, Number.isSafeInteger

Properties: MAX_SAFE_INTEGER, MIN_SAFE_INTEGER, MAX_VALUE, MIN_VALUE, POSITIVE_INFINITY, NEGATIVE_INFINITY, NaN, EPSILON

Missing: toExponential, toPrecision

Map / Set

new Map(), new Set()

Map methods (9): set, get, has, delete, clear, forEach, keys, values, entries + size property

Set methods (7): add, has, delete, clear, forEach, values, entries + size property

Missing: Constructor with iterable argument, Symbol.iterator support

Regex

Regex literals via RE2 backend. Methods: .test(), .exec() with capture groups.

Missing: match, matchAll, lookahead/lookbehind, backreferences (RE2 limitations)

JSON

JSON.parse, JSON.stringify

Backed by Lambda's native JSON parser and formatter. Reviver/replacer/space arguments not yet supported.

Function

.call(), .apply(), .bind()

Date

Date.now(), new Date()

Instance methods (10): getTime, getFullYear, getMonth, getDate, getHours, getMinutes, getSeconds, getMilliseconds, toISOString, toLocaleDateString

Missing: setFullYear, setMonth, setDate, setHours, toUTCString, toDateString, toTimeString

Error

Error, TypeError, RangeError, SyntaxError, ReferenceError

All support .message, .name, and instanceof checks.

Typed Arrays

Full support for all 8 standard typed array types:

Int8Array, Uint8Array, Int16Array, Uint16Array, Int32Array, Uint32Array, Float32Array, Float64Array

Operations: new, get, set, length, fill, subarray

Global Functions

parseInt, parseFloat, isNaN, isFinite, console.log, performance.now(), alert, encodeURIComponent, decodeURIComponent, globalThis

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Benchmark Results — LambdaJS vs Node.js (V8)

Platform: Apple Silicon MacBook Air (M4), macOS
Node.js: v22.13.0 (V8 JIT with TurboFan optimizing compiler)
Methodology: 3 runs per benchmark, median of self-reported execution time
Optimizations applied: P1 (return type propagation), P2 (bump-pointer alloc), P3 (direct ctor stores), P4 (typed instance property reads), P5 (module var arithmetic), P6 (function inlining), P7 (native method dispatch)

Ratio = LambdaJS / Node.js. Values < 1.0× mean LambdaJS is faster.

Summary by Suite

Suite	Geo. Mean	LJS Wins	Node Wins	Total
R7RS	1.3×	5	5	10
AWFY	4.7×	2	12	14
BENG	0.3×	6	4	10
KOSTYA	6.3×	0	7	7
LARCENY	3.8×	2	10	12
JetStream	6.3×	0	9	11
Overall (5 suites)	2.2×	15	38	53

Where LambdaJS Beats Node.js (15 benchmarks)

Benchmark	Suite	LambdaJS	Node.js	Ratio
revcomp	BENG	0.001ms	3.4ms	0.0003×
knucleotide	BENG	0.016ms	5.0ms	0.003×
pidigits	BENG	0.015ms	2.0ms	0.008×
json	AWFY	0.167ms	2.8ms	0.06×
divrec	LARCENY	0.823ms	7.9ms	0.10×
regexredux	BENG	0.305ms	2.5ms	0.12×
fannkuch	BENG	0.529ms	4.1ms	0.13×
tak	R7RS	0.117ms	0.80ms	0.15×
fasta	BENG	1.21ms	6.2ms	0.20×
cpstak	R7RS	0.233ms	1.00ms	0.23×
array1	LARCENY	0.580ms	1.8ms	0.31×
sieve	AWFY	0.136ms	0.376ms	0.36×
fib	R7RS	1.20ms	2.0ms	0.60×
ack	R7RS	9.33ms	13.7ms	0.68×
fibfp	R7RS	1.25ms	1.77ms	0.70×

Strengths:

• Delegating to Lambda's native engines (revcomp, knucleotide, regexredux, pidigits) bypasses JS-level overhead entirely.
• Simple recursive functions (tak, cpstak, fib, ack): MIR JIT generates efficient code for monomorphic call sites.
• Small array/permutation code (divrec, array1, fannkuch, sieve): tight-loop compilation with P5/P6 inlining.
• AWFY json and sieve added as wins after P3/P4/P5 property-access and module-var optimizations.

Where Node.js is Faster

Tier	Count	Key Bottleneck
Comparable (1–2×)	8	nqueens (1.0×), fft (1.6×), primes/larceny (1.7×), primes/kostya (1.8×), paraffins (1.2×), fasta/fib/fibfp
Node 2–5× faster	10	json_gen (2.5×), storage (2.8×), bounce (3.2×), ray (3.2×), list (3.3×), levenshtein (3.5×), queens (3.6×), permute (3.6×), collatz (4.4×), towers (4.9×)
Node 5–20× faster	12	sumfp (5.3×), base64 (6.2×), binarytrees (7.2×), spectralnorm (7.5×), brainfuck (11×), deltablue (12×), deriv (13×), triangl (15×), richards (16×), havlak (18×), diviter (23×), quicksort (5.8×)
Node >20× faster	8	sum (18×), mbrot (10×), puzzle (4.6×), pnpoly (12×), gcbench (29×), nbody/beng (38×), mandelbrot/beng (54×), cd (54×), nbody/awfy (67×), matmul (83×)

Where V8 dominates and why:

• Numeric-heavy loops (sum, nbody, mandelbrot): V8's TurboFan performs type specialization and SIMD optimizations.
• OOP/class-heavy code (richards, deltablue, havlak): V8's hidden classes, inline caches, and on-stack replacement.
• GC-intensive (gcbench, binarytrees, cd): V8's generational GC with concurrent marking.
• String/data processing (base64, brainfuck, json): V8's optimized string representations.

JetStream Benchmarks (Original JS Files)

Measured after v11 Track A performance optimizations (property hash table, array fast path, float prescan widening, integer index fast path, constructor shape pre-allocation, property name interning).

Benchmark	Category	LambdaJS (ms)	Node.js (ms)	Ratio
deltablue	macro	11.0	5.8	1.9×
regex_dna	string	2.4	—	—
cube3d	3D	29.9	11.7	2.6×
splay	data	22.0	7.7	2.9×
crypto_sha1	crypto	22.3	7.5	3.0×
crypto_md5	crypto	21.7	—	—
richards	macro	81.4	5.1	16.0×
crypto_aes	crypto	38.8	—	—
nbody	numeric	260.8	3.1	84.1×
navier_stokes	numeric	569.2	7.5	75.9×
base64	string	390.3	—	—
hashmap	data	TIMEOUT	12.0	—
raytrace3d	3D	FAIL	9.1	—

Geometric mean (exec): LambdaJS 45.0ms vs Node.js 7.2ms → 6.3× (improved from 8.8× in v10).

11 of 13 JetStream JS files run successfully. hashmap times out (GC pressure from 90K constructor calls). raytrace3d has a pre-existing closure capture bug.

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Architecture

JavaScript Source
       │
       ▼
  Tree-sitter Parser (tree-sitter-javascript)
       │
       ▼
  AST Builder (build_js_ast.cpp) ─── 40+ AST node types
       │
       ▼
  MIR Transpiler (transpile_js_mir.cpp)
       │  ├── Capture analysis (multi-level closures)
       │  ├── Type inference (native fast paths)
       │  └── Tail call optimization
       │
       ▼
  MIR IR ──► Native Code (via MIR JIT)
       │
       ▼
  JS Runtime (js_runtime.cpp + js_globals.cpp)
       ├── 24 string methods
       ├── 29 array methods
       ├── 27 math methods
       ├── Prototype chain (max depth 32)
       ├── Typed arrays (8 types)
       └── DOM bridge (Radiant integration)

Component	File	Lines
AST definitions	lambda/js/js_ast.hpp	495
AST builder	lambda/js/build_js_ast.cpp	1,741
MIR transpiler	lambda/js/transpile_js_mir.cpp	9,614
Runtime	lambda/js/js_runtime.cpp	2,170
Globals	lambda/js/js_globals.cpp	819
Runtime header	lambda/js/js_runtime.h	298
DOM bridge	lambda/js/js_dom.cpp	1,772
Typed arrays	lambda/js/js_typed_array.cpp	199
Scoping	lambda/js/js_scope.cpp	248
Total		~18,000