lark-js
An extension to Lark that generates a Javascript standalone
Decision gist · record as of 2026-08-14
Yes, if you need to generate a Javascript parser from a Lark grammar and are comfortable with a dormant package. The tool is stable (Beta status, no known vulnerabilities), has low install friction, and solves a specific problem well. The 1551-day gap since last release is a concern for long-term maintenance, but the repository is not archived and the transpilation approach means it inherits Lark's stability. Install only if you actively need grammar-based parsing in Javascript.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Low install friction with a single pure-Python dependency.
- The package is dormant (last release 2022-05-16, 1551 days ago) but the repository remains active and unarchived; maintenance is minimal but not abandoned.
License · maintenance · safety
MIT (permissive) — MIT license is permissive; you can use, modify, and distribute this package with minimal restrictions, provided you retain the license notice.
last release 2022-05-16 (1551 days) · last repo commit 2024-02-25 · 88 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 74,014 downloads/mo, #14,890 on PyPI
Alternatives
Verify before relying
pip install lark-js
lark-js my_grammar.lark -o my_parser.js- Whether the transpiled Javascript output remains compatible with current Node.js and browser environments
- Current state of the 98% auto-transpilation claim and whether Python-side Lark updates actually sync to this package
What it is and what it does
Lark-js is a Python package that acts as a command-line compiler for Lark grammars, converting `.lark` grammar files into standalone Javascript parsers. It is a port of the Lark parsing toolkit from Python to Javascript, using LALR(1) parsing to guarantee linear-time performance. The generated parsers build parse trees automatically and work in both Node.js and browsers.
The package is primarily a build tool: you install it on Python, write or reuse a Lark grammar file (which is language-agnostic EBNF), and run the `lark-js` command to produce a ready-to-use Javascript parser. The grammar syntax is portable across Python, Javascript, and Julia implementations of Lark, so you can share grammar definitions across projects in different languages.
Use it for
- Generate a Javascript parser from an existing Lark grammar to embed parsing logic in a web application or Node.js service
- Port a Python project that uses Lark to Javascript while reusing the same grammar file unchanged
- Build a domain-specific language (DSL) parser in Javascript without hand-coding the parser logic
- Create interactive parsing tools or IDE-like features in the browser using Lark's step-by-step parsing capability
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you need to generate a Javascript parser from a Lark grammar and are comfortable with a dormant package.
The tool is stable (Beta status, no known vulnerabilities), has low install friction, and solves a specific problem well. The 1551-day gap since last release is a concern for long-term maintenance, but the repository is not archived and the transpilation approach means it inherits Lark's stability. Install only if you actively need grammar-based parsing in Javascript.
Install
lark-js on PyPI
Before you install
Low install friction with a single pure-Python dependency. The package is dormant (last release 2022-05-16, 1551 days ago) but the repository remains active and unarchived; maintenance is minimal but not abandoned.
License in practice
MIT license is permissive; you can use, modify, and distribute this package with minimal restrictions, provided you retain the license notice.
Quickstart
pip install lark-js
lark-js my_grammar.lark -o my_parser.jsVerify before relying
- Whether the transpiled Javascript output remains compatible with current Node.js and browser environments
- Current state of the 98% auto-transpilation claim and whether Python-side Lark updates actually sync to this package
Package facts
| License | MIT permissive |
| Python support | Not specified |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 1 packagelark |
| Maintenance | Dormant 1,551 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 74,014 / month, #14,890 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 4 - BetaIntended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseProgramming Language :: Python :: 2Programming Language :: Python :: 2.7Programming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.4Programming Language :: Python :: 3.5Programming Language :: Python :: 3.6Programming Language :: Python :: 3.7Programming Language :: Python :: 3.8Programming Language :: Python :: 3.9Topic :: Software Development :: Libraries :: Python ModulesTopic :: Text Processing :: GeneralTopic :: Text Processing :: Linguistic |
Evidence: Lark_js-0.1.4-py2.py3-none-any.whl
Tags
Let your AI agent find packages like this
Example. Real query, live index.
You found this page by searching. An agent finds it by wishing: SkillFed indexes 14,416 PyPI packages by what they can do, searchable in plain language.
wish › “javascript parser generator”
- lark-jsLark-js is a command-line tool that generates standalone LALR(1)…
- esprima2Parses and tokenizes JavaScript code up to ECMA 2025 syntax,…
- esprimaEsprima parses ECMAScript (JavaScript) source code into an abstract…
Give your agent the search over MCP, or paste the wish link into any chat.
More Python Modules packages
Converts domain names between Unicode and ASCII-compatible encoding (Punycode) according to IDNA 2008 and Unicode Technical Standard 46, with security validation and broader script coverage than the standard library.
Install it if you work with internationalized domain names, need to validate domains, or use HTTP clients that depend on it transitively.
Setuptools is a Python build backend and package management tool that handles building, distributing, and installing Python packages, including support for C/C++ extension modules.
PyYAML parses and emits YAML 1.1 data format, enabling serialization and deserialization of configuration files and Python objects to and from human-readable YAML text.
Pydantic validates Python data structures against type hints, coercing and checking input at runtime to ensure it matches a declared schema.
Provides reusable metadata objects for use with PEP-593 `typing.Annotated` to express common constraints like bounds, collection sizes, and predicates on types.
Install it if you use or build libraries that need to express type constraints in a standardized, inspectable way—or if you want to annotate your own types with…
Provides runtime tools to inspect and introspect Python type annotations, enabling programmatic examination of type hints at execution time.
See also lark-parser · pycep-parser · lark · pyleri · lark-oapi · spark-parser · textparser · python-hcl2 · tree-sitter-javascript · tree-sitter-typescript