tree-sitter-hujson

A tree-sitter grammar for HuJSON (Human JSON), also known as JWCC (JSON With Commas and Comments).

HuJSON is a strict superset of JSON that adds exactly two features:

• C-style comments: line comments (//) and block comments (/* */)
• Trailing commas: an optional trailing comma after the last element in arrays and objects

All valid JSON is valid HuJSON. HuJSON intentionally rejects every other extension (unquoted keys, hex literals, Infinity/NaN, single-quoted strings, and so on); object keys must be quoted strings, exactly as in standard JSON.

The grammar registers both the .hujson and .jwcc file extensions.

Installation

The grammar is published to npm, PyPI, and crates.io. Each package exposes the compiled language for use with that ecosystem's tree-sitter bindings.

Each example needs the tree-sitter runtime for that language alongside this grammar.

npm (Node.js)

npm install tree-sitter tree-sitter-hujson

const Parser = require("tree-sitter");
const HuJSON = require("tree-sitter-hujson");

const parser = new Parser();
parser.setLanguage(HuJSON);

PyPI (Python)

pip install "tree-sitter-hujson[core]"

import tree_sitter_hujson
from tree_sitter import Language, Parser

parser = Parser(Language(tree_sitter_hujson.language()))

crates.io (Rust)

cargo add tree-sitter tree-sitter-hujson

let mut parser = tree_sitter::Parser::new();
parser
    .set_language(&tree_sitter_hujson::LANGUAGE.into())
    .expect("loading HuJSON grammar");

Go, Swift, and C

These bindings ship in the repository and are consumed directly from the tagged source rather than a package registry.

Editor support

• Zed: install the ggfevans/zed-hujson extension. This is the only editor integration maintained and tested here.
• Other tree-sitter hosts (for example Neovim via nvim-treesitter, or Helix): this is a standard tree-sitter grammar and can be registered through each host's normal grammar mechanism.

Markdown code blocks fenced as ```hujson are highlighted in editors that resolve fence languages by name (verified in Zed). This works through the declared language scope and name; it needs no injections.scm on the grammar side, because the host Markdown grammar supplies the injection.

Provenance

Forked from tree-sitter/tree-sitter-json at commit 001c28d. The upstream grammar already supported comments, so HuJSON support needed only two changes:

1. Trailing commas. The commaSep helper now allows an optional trailing comma:

   function commaSep1(rule) {
     return seq(rule, repeat(seq(",", rule)), optional(","));
   }
   

2. String-only object keys. Upstream tree-sitter-json accepts numeric object keys (choice($.string, $.number)); HuJSON restricts keys to strings to match standard JSON, so bare numeric keys are parse errors. This tightened in v0.2.0.

AI disclosure

This project discloses AI involvement following the ai-disclosure convention. See AI_DISCLOSURE.md for the repo-level default, and per-file headers for any overrides.

Contributing

See CONTRIBUTING.md for development setup, the test suite, and the release process.

Licence

MIT, matching the upstream tree-sitter-json licence.