chartex

You don't need to leave the terminal to visualize your dataset.

Overview

chartex renders compact, beautiful ASCII charts for terminals and scripts from plain JSON/NDJSON/CSV input or a CLI. It is written in ReScript and shipped as a tiny ESM library so you can embed charts in scripts.

Quick highlights

• Small, zero-dependency renderers: Bar, Bullet, Scatter, Sparkline, Pie/Donut/Gauge available in the library.
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• Works with any data shape via accessor-based configs (no pre-transforms required).
• Includes a CLI for piping data-in → ASCII chart-out.
• Thoroughly tested ReScript core with JavaScript-compatible build artifacts.

Note

Requirements: Node.js 22+

Quick Install

npm install chartex

Usage

Build your first chart with the library

1. Create a file example.mjs and paste:

import { Bar } from "chartex";

const data = [
  { name: "Jan", total: 45 },
  { name: "Feb", total: 67 },
  { name: "Mar", total: 82 },
];

const chart = Bar.make(data, {
  key: (d) => d.name,
  value: (d) => d.total,
  style: (d) => (d.total > 60 ? "█" : "░"),
}, { height: 10 });

console.log(chart);

2. Run it:

node example.mjs

CLI

You can install the CLI globally or use npx to run it without installing:

Global install

npm install -g chartex

No-install usage

Basic usage:

npx chartex [options] [file]

Note

Full CLI options reference: docs/cli.md

Documentation

📖 Full docs at metalbolicx.github.io/chartex

• API reference for library usage
• Examples and guides

Contributing

Contributions welcome — open issues or PRs.

npm run res:build   # compile ReScript
npm run res:test    # run tests
npm run cli:build   # bundle CLI (if CLI changed)
npm run build       # build dist/ artifacts (tsdown)
npm run res:clean   # clean ReScript outputs

License

Released under MIT by @MetalbolicX.