Escargot v5.0.3

Changes since v5.0.2

Memory and garbage collection

• Reduce temporary object, argument-list, array, captured-binding, and
  control-flow allocations.
• Stream UTF-8 script sources through bounded parser windows and prevent
  string literals from retaining entire source files.
• Flatten StringView chains, release cold compressible string pages, and
  prevent use-after-free of reloadable and compressible string buffers.
• Update GCutil to reduce leaks and avoid scanning explicitly freed objects.
• Fix incremental GC rescanning and clear vacated Vector slots before scans.

Runtime performance

• Optimize object property storage, transition sharing, inline caches, and
  lexical scope storage.
• Specialize TypedArray indexed access and improve Map and Set size tracking.
• Optimize switch compilation, value tagging, equality checks, and numeric
  boxing, including Math results.

Correctness and portability

• Fix IteratorClose when an iterator's return method is null.
• Preserve assignment targets after rejected awaits and handle arguments
  bindings without indexed storage.
• Preserve ExposableObject property enumeration and correct Object
  constructor property-name checks.
• Reject BigInt values that are too large to materialize.
• Fix compiler and linker issues involving Clang, MSVC, GCC, PIC, and LTO.
• Fix a Test262 agent startup race and improve CI failure diagnostics.

Embedding and tooling

• Add Memory::setStackBottom and use it in the shell to establish GC roots.
• Enable compressed pointers by default on supported 64-bit hosts.
• Extend DevTools debugger previews to collections and additional objects.
• Add a shell option for incremental GC and improve memory profiling support.
• Publish Android Maven artifacts through the Android release workflow.
• Expand scheduled engine comparisons, including native ARM and Hermes.

Contributors

• @ksh8281
• @matetokodi
• @kwy404

Changes since v5.0.1

• Implement Inline cache of instance of operation (#1667)
• Fix memory corruption in GC disclaim callbacks (#1668)
• Optimize computed goto labels initialization in interpret() (#1668)
• Fix Atomics wait/notify race conditions with per-waiter condition variables (#1669)
• Smoke-test all 3 Maven release artifacts in android-release.yml

Contributors

• @ksh8281

Escargot v5.0.1

Patch release — build/packaging fixes and a new UBSan CI gate, no
contributor or spec-behavior changes since v5.0.0.

Fixed

• Maven escargot-ubuntu/escargot-mac host jars no longer fail with
  UnsatisfiedLinkError: libwalrus.so when loaded standalone — the host
  jar build no longer enables ESCARGOT_WASM, matching the real Android
  AAR build, and defensively bundles libwalrus.* if it's ever present.
• Tizen RPM build (rpmbuild) no longer aborts with "Installed (but
  unpackaged) file(s) found" — libgc-lib.so is now declared in
  escargot.spec's %files for every profile subpackage.
• RTOS baseline CI: QEMU boot-test timeout raised from 60s to 120s so
  SunSpider isn't cut off mid-run.

Added

• New ESCARGOT_UBSAN CMake option, enabled by default on x64 Release CI
  legs, catching several latent UB issues (fixed in this release):
  signed-overflow multiply in Math.imul, UB shifts of signed int32_t in
  left-shift/toInt32/IEEE754 code, an out-of-range 1 << paramIndex in
  esprima, null-pointer-at-zero-length memcpys, an undersized shift
  denominator in double-conversion's strtod, and a null-allocator
  reference bind in rapidjson's stack allocator.

Release Note v5.0.0

• Fully support ECMAScript 2026
• Add Node-API (N-API) support with a v10-compatible, C-style hosting API — see docs/n-api.md
• Add a Chrome DevTools Protocol debugger (breakpoints, stepping, scope/call-stack inspection, eval, restart)
• Add bare-metal/RTOS reference ports (FreeRTOS, NuttX) and arm-none-eabi support
• Add iOS device (iphoneos) build support
• Add an option to use the system-provided ICU instead of Escargot's vendored one, trading some Intl/Temporal functionality for a smaller binary
• Numerous engine performance and memory improvements (RegExp compile cache, inline caches, GC)
• Fix misc bugs/issues

Language Specification (ECMAScript 2026)

Escargot implements full of ECMAScript 2026 except a few minor features.

Multi-Platform Build

What's Implemented

• Full Temporal API: PlainDate, PlainTime, PlainDateTime, PlainYearMonth, PlainMonthDay, ZonedDateTime, Duration, Instant, Now
• ShadowRealm constructor, prototype.evaluate, prototype.importValue, wrapped functions (early-stage TC39 proposal, included in official builds via -DESCARGOT_SHADOWREALM=ON)
• Iterator.concat
• Array.fromAsync
• Explicit Resource Management refinements
• Node-API (N-API) hosting API with safe GC lifetimes
• Chrome DevTools debugger

New Contributors

• @ivmai made their first contribution in #1510
• @matetokodi made their first contribution in #1531
• @kulcsaradam made their first contribution in #1545
• SAY-5 reported and fixed an out-of-bounds read in the lexer's comment/hashbang skipping (0a79d6c1f)
• @el-s1na made their first contribution in #1581
• @envia made their first contribution in #1627

Contributors

Thanks also to everyone who kept contributing this cycle:

• @kwonjeomsim (Jeonbuk National University)
• @clover2123 (Jeonbuk National University) — inline cache refactoring
• @2Jaeheon (Jeonbuk National University)

Full Changelog: v4.3.0...v5.0.0

Release Note v4.3.0

• Fully support ECMAScript 2025
• Update Yarr module based on [WebKitGTK 2.48.3]
• Fix misc bugs/issues

Language Specification (ECMAScript 2025)

Escargot implements full of ECMAScript 2025 except a few minor features.

Multi-Platform Build

What's Implemented

• Explicit Resource Management
• Uint8Array to/from Base64
• Math.sumPrecise
• Error.isError
• RegExp.escape
• Float16 on TypedArrays, DataView, Math.f16round
• Promise.try
• Sync Iterator helpers
• JSON Modules
• Import Attributes
• RegExp Modifiers
• New Set methods
• Duplicate named capture groups
• Intl.DurationFormat
• Intl.NumberFormat V3
• Intl Enumeration API
• Intl.DisplayNames v2
• Extend TimeZoneName Option Proposal
• Intl.Segmenter: Unicode Segmentation in JavaScript
• Intl.DateFormat.prototype.formatRange

New Contributors

• @Moxie07 made their first contribution in #1419
• @2Jaeheon made their first contribution in #1451
• @kwonjeomsim made their first contribution in #1454

Full Changelog: v4.2.0...v4.3.0

Release Note v4.2.0

• Fully support ECMAScript 2024
• Update Yarr module based on WebKitGTK 2.44.2
• Fix misc bugs/issues
• Support macOS build on arm64 (M1)

Language Specification (ECMAScript 2024)

Escargot implements full of ECMAScript 2024 except a few minor features.

• Not Supported Features
  • RegExp lookbehind assertions

Multi-Platform Build

Release Note v4.1.1

• Fully support ECMAScript 2023
• Fix misc bugs/omitted functions
• Update TCO debug mode

Release Note v4.1.0

• Update WebAssembly engine
• Apply several optimizations for performance improvement
• Fix misc bugs/issues
• Add a build option ESCARGOT_USE_EXTENDED_API to enable non-standard features such as Template, Error Callback used by specific third-parties.

WebAssembly

• Using Walrus engine linked by wasm-c-api
• Walrus supports interpreter and JITC mode both
• Walrus JITC employs sljit as backend compiler

Optimization

• Advanced Inline Caching: broaden the target range of object's property access cases
• Tail Call Optimization (TCO): apply general TCO approach and specialized TCO for recursive tail calls.

Release Note v4.0.0

• Support ECMAScript2022
• Enable WebAssembly
• Support multi platform build
• Several optimizations for memory and performance updated
• Fixed major/minor bugs

Language Specification (ECMAScript 2022)

Escargot implements full of ECMAScript 2022 except a few minor features.

• Not Supported Features
  • RegExp lookbehind assertions

WebAssembly

• Using wabt engine linked by wasm-c-api
• Support WebAssembly Core Specification Release 1.0 (https://www.w3.org/TR/wasm-core-1/)
• Support WebAssembly JavaScript Interface 1.0 (https://www.w3.org/TR/wasm-js-api-1/)

Multi-Platform Build

Release Note v3.0.0

• Escargot now fully supports ES10
• Debugger core features updated
• Several optimizations for memory and performance updated
• Fixed major/minor bugs

Language Specification (ECMAScript 2019)

Escargot implements full of ECMAScript 2019 except a few minor features.

• Not Supported Features
  • Shared-Memory
  • Atomics
  • RegExp lookbehind assertions

Debugger Implementation

• Breakpoint management
• Execution control
• Getting debug info(backtrace, variable)
• Debugger script tools

Enhancements

• Source code compression
• Lazy AtomicString initialization
• Improve performance of property map
• Improve Vector extension logic