Escargot 4.2.0

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

OS	Architecture
Ubuntu	x86/x64/arm/aarch64
macOS	x64/aarch64
Windows	x86/x64
Android	x86/x64/arm/aarch64

Escargot 4.1.1

Release Note v4.1.1

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

Escargot 4.1.0

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.

Escargot 4.0.0

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

OS	Architecture
Ubuntu	x86/x64/arm/aarch64
macOS	x64
Windows	x86
Android	x86/x64/arm/aarch64

Escargot 3.0.0

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

Escargot 2.0.0

Release Note v2.0.0

• Escargot now fully supports ES6.0.
• Several optimizations for memory and performance updated.
• Fixed major/minor bugs

Language Specification (ECMAScript 2015)

Escargot implements full of ECMAScript 6.0.

Enhancements

• Parsing Optimization (over 50% parsing performance improvement)
• Revise Public API
• Update Submodules (Yarr, GC) to the latest version

Escargot 1.0.0

Release Note v1.0.0

Escargot is a memory optimized JavaScript engine for mid-range devices such as mobile phone, tablet and TV. This is the first stable release of Escargot.

Language Specification (ECMAScript)

Escargot implements full of ECMAScript 5.1 and part of ECMAScript 6.0.

ES5.1

ES5 specification is fully supported with Escargot.

ES6.0

supported

Object type	Implemented Feature	Property Type	Note
TypedArray Objects	TypedArray ()	constructor	Currently it works expectedly only with arraylength less than 210000000
	TypedArray (length)	constructor
	TypedArray (buffer [, byteOffset [, length]])	constructor
	TypedArray.prototype.indexOf (searchElement [, fromIndex])	method
	TypedArray.prototype.lastIndexOf (searchElement [, fromIndex])	method
	TypedArray.prototype.set (array [, offset])	method
	TypedArray.prototype.set (typedArray [, offset])	method
	TypedArray.prototype.subarray ([begin [, end]])	method
	TypedArray.BYTES_PER_ELEMENT	data property
	TypedArray.prototype.BYTES_PER_ELEMENT	data property
	TypedArray.prototype.constructor	data property
	TypedArray.prototype.copyWithin (target, start [, end])	method
	TypedArray.prototype.every (callbackfn [, thisArg])	method
	getter of TypedArray.prototype.byteLength	accessor property
	getter of TypedArray.prototype.byteOffset	accessor property
	getter of TypedArray.prototype.length	accessor property
	getter of TypedArray.prototype.buffer	accessor property
ArrayBuffer Objects	ArrayBuffer (length)	constructor
	ArrayBuffer.isView (arg)	function
	getter of ArrayBuffer.prototype.byteLength	accessor property
	ArrayBuffer.prototype.constructor	data property
	ArrayBuffer.prototype.slice (start, end)	method
DataView Objects	DataView (buffer [, byteOffset [, byteLength]])	constructor
	getter of DataView.prototype.buffer	accessor property
	getter of DataView.prototype.byteLength	accessor property
	getter of DataView.prototype.byteOffset	accessor property
	DataView.prototype.constructor	data property
	DataView.prototype.[get | set][Float32 | Float64 | Int8 | Int16 | Int32 | Uint8 | Uint16 | Uint32] (byteOffset [, littleEndian))	method
Promise Objects	Promise (executor)	constructor
	Promise.all (iterable)	function
	Promise.race (iterable)	function
	Promise.reject (r)	function
	Promise.resolve (x)	function
	Promise.prototype.catch (onRejected)	method
	Promise.prototype.then (onFulfilled, onRejected)	method

Modules

• Parser (based on esprima) : translate the source code into AST nodes
• ByteCodeGenerator : generate register-based bytecode
• Interpreter : interpret the bytecode sequentially
• GC (based on Boehm-Demers-Weiser GC) : automatically free memory