This is Longbridge's JIT-enabled distribution of rquickjs. The published
package is named quickjs-jit, while its Rust library name remains rquickjs
for source compatibility:
rquickjs = { package = "quickjs-jit", version = "=0.12.2" }
rquickjs-jit = { package = "quickjs-jit-runtime", version = "=0.12.2", features = ["compiler"] }The distribution and JIT runtime must use the same patch version. The JIT ABI
includes internal QuickJS structure layouts, so mixing runtime, core, or sys
crate patch versions may compile but will be rejected during JIT startup.
quickjs-jit-runtime 0.12.3 has not been published yet. Consumers testing the
0.12.3 source must pin the distribution and runtime to the same Git revision
and use Cargo source patches from that revision for both quickjs-jit-core and
quickjs-jit-sys. Do not combine the published 0.12.2 runtime with 0.12.3
core or sys crates.
This library is a high level bindings of the QuickJS-NG JavaScript engine, a fork of the QuickJS Javascript engine. Its goal is to be an easy to use, and safe wrapper similar to the rlua library.
QuickJS is a small and embeddable JavaScript engine. It supports the ES2020 specification including modules, asynchronous generators, proxies and BigInt. It optionally supports mathematical extensions such as big decimal floating point numbers (BigDecimal), big binary floating point numbers (BigFloat) and operator overloading.
- Small and easily embeddable: just a few C files, no external dependency, 210 KiB of x86 code for a simple hello world program.
- Fast interpreter with very low startup time: runs the 75000 tests of the ECMAScript Test Suite in about 100 seconds on a single core of a desktop PC. The complete life cycle of a runtime instance completes in less than 300 microseconds.
- Almost complete ES2020 support including modules, asynchronous generators and full Annex B support (legacy web compatibility).
- Passes nearly 100% of the ECMAScript Test Suite tests when selecting the ES2020 features. A summary is available at Test262 Report.
- Can compile JavaScript sources to executables with no external dependency.
- Garbage collection using reference counting (to reduce memory usage and have deterministic behavior) with cycle removal.
- Mathematical extensions: BigDecimal, BigFloat, operator overloading, bigint mode, math mode.
- Command line interpreter with contextual colorization implemented in JavaScript.
- Small built-in standard library with C library wrappers.
- Full integration with async Rust
- The ES6 Promises can be handled as Rust futures and vice versa
- Easy integration with almost any async runtime or executor
- Flexible data conversion between Rust and JS
- Many widely used Rust types can be converted to JS and vice versa
- Support for user-defined allocators
- The
Runtimecan be created using custom allocator - Using Rust's global allocator is also fully supported
- The
- Support for user-defined module resolvers and loaders which also can be combined to get more flexible solution for concrete case
- Support for bundling JS modules as a bytecode using
embedmacro - Support for deferred calling of JS functions
- Full support of ES6 classes
- Rust data types can be represented as JS classes
- Data fields can be accessed via object properties
- Both static and instance members is also supported
- The properties can be defined with getters and setters
- Support for constant static properties
- Support for holding references to JS objects
(Data type which holds refs should implement
Tracetrait to get garbage collector works properly) - Support for extending defined classes by JS
Every JIT optimization must include benchmarks against QuickJS, Bun, and quickjs-jit, with the complete per-scenario comparison in this README. Bun default is the external performance target; the previous JIT revision tracks regressions, and the interpreter establishes whether native execution is profitable. See the repository rules and next optimization targets.
Complete 24-scenario matrix: candidate4, measured 2026-09-10. Host compute regression remains unresolved: automatic hot reload is 0.9444x baseline speed [0.9373, 0.9518], and interpreter steady-state is 0.9329x [0.9303, 0.9354]. The host regression budget has not passed; this is measured candidate evidence, not an acceptance claim. See the implementation, paired controls, and host findings.
Measured source snapshot: candidate4, binary SHA-256 b758218bdd1d746083f34693a78d42607bc663086fa3e64e2d2f98384d17c2a3.
QuickJS and automatic use that same binary; QuickJS means JIT detached. Bun
1.4.0 uses default flags [], executable /home/jason/.bun/bin/bun,
SHA-256 33d56b070be6a9e3da0ab013038b43d1645d0534ca811ecdba4472599117eb4b. Host: 13th Gen Intel(R) Core(TM) i7-13700KF; Linux-7.1.9-arch1-2-x86_64-with-glibc2.44; pinned
CPU 2; governor powersave; rustc 1.98.1 (48a229cea 2026-09-01). Exact compiler/build,
source revision/patch manifests, and host details belong to the linked archive;
this renderer does not infer unrecorded source revisions from binary names.
Protocol shared-js-fixed-warmup-v2: one initial call, then 64 batches of ten calls, followed
by one measured ten-call batch. All engines run the same driver, input policy,
sequential Promise completion, and result storage; checksums run after timing.
Driver SHA-256 60408ad6d28c58e7f20161c17a5db11fc142685fdd07ec7dbf35d7bb02a8f7c5. Each row has five discarded processes/config and
30 interleaved retained fresh-process pairs/config. Absolute timings are
medians in ms per ten workload calls. Speed ratios are geometric means of
paired reference-latency/automatic-latency ratios, with deterministic 10,000
paired percentile-bootstrap resamples (seed 20260909); they are not ratios of the
displayed medians. Above 1x is faster than the named baseline. Intervals crossing
1x are statistically tied, with the slower/faster range shown explicitly.
These are fixed-warmup latencies. Samples are not excluded because they lack native entries, compile during the window, fall back, or run slowly. QuickJS includes one outer Rust call/Promise bridge; both engines include shared driver array/closure work. Fixed counters surround the batch before checksum execution and aggregate driver plus workload, not a named function. The quiet count means zero pending jobs/snapshot bytes at both endpoints and no observed installation or compile-time increment, not proof of an engine's peak tier. Native counts do not establish Bun's tier.
Readiness diagnostics are collected later only for QuickJS; their timings and
cumulative counters must not replace fixed-window evidence or be divided into
Bun's differently conditioned latency. This latency matrix contains no JS
throughput windows, matched settled-state Bun samples, per-call P99, or host
snapshot measurement. Those requirements remain separate; mixed-quotes is a
pure JS kernel, not GPUI snapshot timing. Legacy gate reporting rejects this
protocol. Raw evidence and machine-readable summary.
| Workload | QuickJS ms | Bun ms | automatic ms | automatic / QuickJS speed [95% CI] | automatic / Bun speed [95% CI] |
|---|---|---|---|---|---|
| mixed-quotes | 2.349774 | 0.147462 | 2.736590 | 0.8595x [0.8568, 0.8627] | 0.0542x [0.0536, 0.0549] |
| quickjs-int-arith | 5.357147 | 0.131634 | 1.634172 | 3.2921x [3.2831, 3.3018] | 0.0831x [0.0811, 0.0855] |
| quickjs-bitops | 1.144004 | 0.152575 | 0.205012 | 5.5814x [5.5525, 5.6111] | 0.7575x [0.7399, 0.7778] |
| quickjs-fibonacci | 0.839358 | 0.144318 | 0.359949 | 2.3896x [2.3486, 2.4372] | 0.4116x [0.4054, 0.4184] |
| numeric | 0.488411 | 0.129795 | 0.021608 | 22.4911x [22.2385, 22.7115] | 6.1432x [5.9995, 6.3035] |
| scalar-loop | 0.489399 | 0.132878 | 0.021566 | 22.2350x [21.4209, 22.7450] | 6.0842x [5.8316, 6.3037] |
| call-heavy | 1.261803 | 0.006315 | 0.312781 | 4.0333x [3.9902, 4.0812] | 0.0203x [0.0202, 0.0205] |
| generic-call-entry | 0.934287 | 0.004954 | 0.231675 | 4.0356x [4.0086, 4.0622] | 0.0225x [0.0213, 0.0251] |
| generic-call-fallback | 1.274439 | 0.008116 | 3.786595 | 0.3376x [0.3360, 0.3391] | 0.0022x [0.0021, 0.0022] |
| property-heavy | 1.029746 | 0.007804 | 0.325760 | 3.1635x [3.1323, 3.1971] | 0.0243x [0.0238, 0.0252] |
| fibonacci-iterative | 29.467614 | 0.936226 | 0.878952 | 33.7586x [33.3822, 34.1502] | 1.0773x [1.0613, 1.0940] |
| fibonacci-recursive | 9.865694 | 0.549300 | 9.895509 | 0.9992x [0.9965, 1.0023]; statistically tied; between 0.3% slower and 0.2% faster | 0.0555x [0.0549, 0.0560] |
| collections | 1.575133 | 0.137655 | 1.576190 | 1.0005x [0.9968, 1.0055]; statistically tied; between 0.3% slower and 0.5% faster | 0.0877x [0.0871, 0.0883] |
| strings-json | 1.972826 | 0.187261 | 2.025572 | 0.9753x [0.9704, 0.9801] | 0.0901x [0.0879, 0.0923] |
| calls-closures | 3.489562 | 0.228020 | 3.519299 | 0.9897x [0.9845, 0.9946] | 0.0619x [0.0596, 0.0640] |
| adversarial | 0.914932 | 0.125981 | 0.916971 | 1.0023x [0.9906, 1.0145]; statistically tied; between 0.9% slower and 1.4% faster | 0.1394x [0.1361, 0.1434] |
| float64-dense | 2.281055 | 0.148484 | 0.362700 | 6.3050x [6.2579, 6.3595] | 0.4153x [0.4097, 0.4221] |
| strings-regexp | 19.591037 | 1.309532 | 20.241909 | 0.9663x [0.9622, 0.9690] | 0.0648x [0.0643, 0.0652] |
| arrays-typed | 4.160535 | 0.138155 | 2.534226 | 1.6407x [1.6359, 1.6455] | 0.0548x [0.0544, 0.0552] |
| objects-polymorphic | 6.268702 | 0.202083 | 6.652939 | 0.9425x [0.9385, 0.9462] | 0.0304x [0.0303, 0.0306] |
| calls-recursion-closures | 6.464855 | 0.206337 | 6.552003 | 0.9888x [0.9854, 0.9927] | 0.0317x [0.0315, 0.0321] |
| json-codec | 77.302303 | 7.727146 | 78.995999 | 0.9843x [0.9758, 0.9981] | 0.0978x [0.0974, 0.0981] |
| map-set-bigint | 17.486868 | 0.971720 | 16.617827 | 1.0430x [1.0259, 1.0590] | 0.0591x [0.0584, 0.0598] |
| exceptions-promises-async | 2.323206 | 0.288878 | 3.487680 | 0.6624x [0.6530, 0.6694] | 0.0825x [0.0811, 0.0838] |
| Workload | quiet fixed batches / 30 | native entry delta | Tier2 entry delta | deopt delta | later readiness median ms |
|---|---|---|---|---|---|
| mixed-quotes | 30 | 6990 | 6980 | 0 | 2.752615 |
| quickjs-int-arith | 30 | 10 | 10 | 0 | 1.618791 |
| quickjs-bitops | 30 | 10 | 10 | 0 | 0.204897 |
| quickjs-fibonacci | 30 | 10 | 0 | 0 | 0.371977 |
| numeric | 30 | 10 | 10 | 0 | 0.021836 |
| scalar-loop | 30 | 10 | 10 | 0 | 0.021813 |
| call-heavy | 30 | 10 | 10 | 0 | 0.313397 |
| generic-call-entry | 30 | 10 | 10 | 0 | 0.225981 |
| generic-call-fallback | 30 | 20000 | 20000 | 0 | 3.785854 |
| property-heavy | 30 | 10 | 10 | 0 | 0.319246 |
| fibonacci-iterative | 30 | 10 | 10 | 0 | 0.880027 |
| fibonacci-recursive | 30 | 0 | 0 | 0 | 9.921852 |
| collections | 30 | 0 | 0 | 0 | 1.586696 |
| strings-json | 30 | 0 | 0 | 0 | 2.031513 |
| calls-closures | 30 | 0 | 0 | 0 | 3.521440 |
| adversarial | 30 | 0 | 0 | 0 | 0.935643 |
| float64-dense | 30 | 10 | 10 | 0 | 0.364465 |
| strings-regexp | 30 | 0 | 0 | 0 | 20.256235 |
| arrays-typed | 30 | 20 | 20 | 0 | 2.535597 |
| objects-polymorphic | 30 | 0 | 0 | 0 | 6.687356 |
| calls-recursion-closures | 30 | 0 | 0 | 0 | 6.534747 |
| json-codec | 30 | 0 | 0 | 0 | 79.607234 |
| map-set-bigint | 30 | 0 | 0 | 0 | 16.940369 |
| exceptions-promises-async | 30 | 0 | 0 | 0 | 3.538708 |
All 24 scenarios are included. Zero-entry rows measure attached-runtime fallback;
aggregate native/Tier2 counts do not identify the tier of an individual callee.
The original branch-leaf call probe can now use compiled caller plus direct ABI;
generic-call-fallback preserves effectful non-direct calls and native entries.
It does not prove a compiled caller invokes the C CALL helper on every iteration.
Historical matrix: the 2026-09-06 47aeb11 results used different warmup
and host timing boundaries and must not be divided into these v2 timings to
claim an optimization gain. The historical full table and tier diagnostics,
raw samples,
versions, flags, and reproduction,
and derived intervals remain
available. Benchmark commands and protocol details.
This crate doesn't aim to provide system and web APIs. The QuickJS library is close to V8 in that regard. If you need APIs from WinterGC or Node, then you can take a look at the follow community projects:
- AWS LLRT Modules: Collection of modules that micmic some of the
NodeAPIs in pure Rust - Rquickjs Extra: Collection of modules that complement
AWS LLRT Modulesin pure Rust
The community has also built various utilities which might be relevant to you:
- Rquickjs Serde: Serde serializer and deserializer for rquickjs Value
This bindings is feature complete, mostly stable and ready to use.
The error handling is only thing which may change in the future.
Some experimental features like parallel may not works as expected. Use it for your own risk.
Rquickjs needs to compile a C-library which has it's own limitation on supported platforms, furthermore it needs to generate bindings for that platform.
As a result rquickjs might not compile on all platforms which rust supports.
In general you can allways try to compile rquickjs with the bindgen feature, this should work for most platforms.
Rquickjs ships bindings for a limited set of platforms, for these platforms you don't have to enable the bindgen feature.
See below for a list of supported platforms.
| platform | shipped bindings | tested | supported by quickjs |
|---|---|---|---|
| x86_64-unknown-linux-gnu | ✅ | ✅ | ✅ |
| i686-unknown-linux-gnu | ✅ | ✅ | ✅ |
| aarch64-unknown-linux-gnu | ✅ | ✅ | ✅ |
| loongarch64-unknown-linux-gnu | ✅ | ✅ | ✅ |
| x86_64-unknown-linux-musl | ✅ | ✅ | ✅ |
| aarch64-unknown-linux-musl | ✅ | ✅ | ✅ |
| loongarch64-unknown-linux-musl | ✅ | ✅ | ✅ |
| x86_64-pc-windows-gnu | ✅ | ✅ | ✅ |
| i686-pc-windows-gnu | ✅ | ✅ | ✅ |
| x86_64-pc-windows-msvc | ✅ | ✅ | ❌ experimental! |
| aarch64-pc-windows-msvc | ✅ | ❌ | ❌ experimental! |
| x86_64-apple-darwin | ✅ | ✅ | ✅ |
| aarch64-apple-darwin | ✅ | ❌ | ✅ |
| wasm32-wasip1 | ✅ | ✅ | ✅ |
| wasm32-wasip2 | ✅ | ✅ | ✅ |
| other | ❌ | ❌ | Unknown |
This library is licensed under the MIT License