jq-pointer

Paste JSON, click the value you want, get the jq expression that extracts it - the reverse of every jq playground.

Development

Requires Node 20.19+ (or 22.12+) and pnpm.

pnpm install
pnpm dev

Command	What it does
pnpm dev	Start the dev server
pnpm build	Type-check and build the static bundle
pnpm lint	Run oxlint
pnpm format	Check formatting with oxfmt
pnpm format:write	Format the tree with oxfmt
pnpm typecheck	Run the TypeScript compiler
pnpm test	Run the test suite (includes the perf spike)
pnpm bench	Run only the performance spike
pnpm check	lint + format + typecheck + test

Input handling

Parsing is strict JSON.parse only - there is no tolerant repair. Invalid input shows a positioned error with a caret excerpt of the offending line. NDJSON pastes and JavaScript-literal pastes (trailing commas, single quotes, unquoted keys) are detected heuristically and named in the error message without any repair.

Two JSON.parse behaviours are inherited deliberately and produce no warning:

• Duplicate keys: the last occurrence wins ({"a": 1, "a": 2} parses as {"a": 2}).
• Number precision: numbers beyond IEEE 754 double precision lose precision (9007199254740993 parses as 9007199254740992).

Performance spike (D7)

The spike result and the main-thread vs worker decision are documented in docs/perf-spike.md.

jq oracle

Grammar property tests use the official jq 1.7.1 Linux AMD64 binary as a pinned oracle. CI downloads it as jq-1.7.1; the oracle tests skip on Windows because that binary cannot execute locally.

Self-hosting

Deploy from a tagged release, not an arbitrary commit. Every GitHub Release carries a prebuilt static dist archive (jq-pointer-<version>.zip and .tar.gz) plus a SHA256SUMS file.

1. Download and verify

VERSION=0.1.0
curl -fLO "https://github.com/jishnuteegala/jq-pointer/releases/download/v$VERSION/jq-pointer-$VERSION.tar.gz"
curl -fLO "https://github.com/jishnuteegala/jq-pointer/releases/download/v$VERSION/SHA256SUMS"
sha256sum --check --ignore-missing SHA256SUMS
mkdir -p dist && tar -xzf "jq-pointer-$VERSION.tar.gz" -C dist

The app is a single static page plus real static routes (/design-system/, /llms.txt); any static file server works with no rewrite rules required.

2. Pick a host

Cloudflare Pages

npx wrangler pages deploy dist --project-name jq-pointer

Or use git integration: import the repo in the Cloudflare dashboard with build command pnpm build and output directory dist. The bundled _headers file sets the security headers automatically.

Vercel

npx vercel deploy dist --prod

GitHub Pages

git checkout --orphan gh-pages && git rm -rf . && cp -r dist/. . && rm -rf dist
git add -A && git commit -m "deploy" && git push -f origin gh-pages

Then enable Pages for the gh-pages branch in the repo settings.

VPS with nginx (any cloud - AWS/GCP/Azure/other)

server {
    listen 80;
    server_name jq.example.com;
    root /var/www/jq-pointer;
    index index.html;
    location /assets/ {
        add_header Cache-Control "public, max-age=31536000, immutable";
    }
}

Copy the extracted dist/ to /var/www/jq-pointer and reload nginx.

VPS with Caddy

jq.example.com {
    root * /var/www/jq-pointer
    file_server
}

Docker

FROM nginx:alpine
COPY dist /usr/share/nginx/html
EXPOSE 80

docker build -t jq-pointer . && docker run -p 8080:80 jq-pointer

Or with compose, no image build needed:

services:
  jq-pointer:
    image: nginx:alpine
    volumes:
      - ./dist:/usr/share/nginx/html:ro
    ports:
      - "8080:80"

Releases

Releases are managed by release-please: merging the release PR tags the version, and the release stays a draft until the dist archives are built, checksummed, and uploaded.

License

MIT - see LICENSE