ARK JS Runtime Module

• Directory Structure

• Constraints

• Build

  • Available APIs
  • Usage Guidelines

• Repositories Involved

Introduction

ARK JS Runtime is the runtime used by JavaScript (JS) applications on OpenHarmony. It consists of the JS object allocator, garbage collector (GC), a standard library compliant with ECMAScript specifications, ARK bytecode interpreter, inline caches that store hidden classes, and the ARK Foreign Function Interface (AFFI).

ARK JS runtime architecture

Directory Structure

/ark/js_runtime
├─ ecmascript             # JS object definition
│   ├─ base               # Base helper class
│   ├─ builtins           # ECMAScript library
│   ├─ class_linker       # Bytecode pre-processing module
│   ├─ compiler           # JS compiler
│   ├─ hprof              # Memory analysis utility class
│   ├─ ic                 # Inline cache module
│   ├─ interpreter        # JS interpreter
│   ├─ jobs               # Queue of jobs
│   ├─ js_vm              # ARK command line tool
│   ├─ mem                # Memory management module
│   ├─ napi               # External native interface
│   ├─ regexp             # Regular expression engine module
│   ├─ snapshot/mem       # Snapshot module
│   ├─ tests              # Unit test cases
│   ├─ thread             # Thread pool
│   ├─ tooling            # JS debugger
│   └─ vmstat             # Runtime status utility classes
└─ test                   # Module test cases

Constraints

• Only the bytecode file generated by the ARK JS frontend can be run.
• Only support ES2015 standard and strict mode ("use strict").
• Don't support dynamically create functions via string (e.g., new Function("console.log(1))).

Build

./build.sh --product-name Hi3516DV300 --build-target ark_js_runtime

Available APIs

For details, see NAPI.

Usage Guidelines

For details about how to generate JS bytecodes, see Using the Toolchain.

To run bytecodes:

cd out/release

LD_LIBRARY_PATH=clang_x64/ark/ark:clang_x64/global/i18n:../../prebuilts/clang/ohos/linux-x86_64/llvm/lib/ ./clang_x64/ark/ark/ark_js_vm helloworld.abc _GLOBAL::func_main_0

Repositories Involved

ARK Runtime Subsystem

ark/runtime_core

ark/js_runtime

ark/ts2abc