@deckyard/jsonpath

RFC 9535 JSONPath queries for Jennifer, over json.Value. The whole RFC: name, wildcard, index, slice and filter selectors, descendant segments, comparisons and logic, and the functions length, count, match, search and value, with I-Regexp patterns. Every case of the official JSONPath Compliance Test Suite passes. Results come as values, as JSON Pointers for the json writers, or as normalized paths.

Documentation

Install

jvc add @deckyard/jsonpath

Or unpack src/ from a release archive (deckyard-jsonpath-<version>.tar.gz) into vendor/deckyard/jsonpath/.

Usage

use fs;
use io;
use json;
import "@deckyard/jsonpath/" as jsonpath;

def doc as json.Value init json.decode(fs.readString("store.json"));

for (def title in jsonpath.query($doc, "$..book[?@.price < 10].title")) {
    io.printf("%s\n", json.asString($title));
}

def p as jsonpath.Path init jsonpath.compile("$..book[?search(@.author, 'Tolkien')]");
for (def m in jsonpath.find($doc, $p)) {
    io.printf("%s at %s\n", json.encode($m.value), $m.pointer);
}

Requirements

Jennifer 0.25.0 or newer, default or jennifer-tiny binary. No capability.

Development

tools/check-all.sh                   # the full gate, as CI runs it
jennifer test src/jsonpath_test.j    # unit tests and the compliance suite
tools/check-docs.sh                  # docs against the code
tools/pack.sh dist                   # build the release archive

testdata/cts is the vendored compliance suite (BSD-2, see its README).

Licence

LGPL-3.0-only, see LICENSE. Copyright (C) 2026 mplx <mplx@jennifer-lang.dev>.