Tweakit

A dependency-free, code-split, real-time parameter panel. Hand it a plain schema and it builds a live control for each value: sliders, toggles, dropdowns, a wide-gamut OKLCH color picker, gradient, shadow, cubic-bézier and motion editors, a spring tuner, a four-sided length (padding, margin or radii) on one row, monitors, a 2D point pad, and more.

Docs & live examples →

Why tweakit

Tweakpane, lil-gui and Leva are all good panels: Tweakpane for its plugin ecosystem, lil-gui for the smallest footprint, Leva if your app is React hooks throughout. Tweakit is for when the values you're tuning are color and motion:

• Wide-gamut color. An OKLCH picker that reaches past sRGB into Display P3 and Rec. 2020 and says which gamut a color is in, eleven notations, and the value handed back exactly as you wrote it until you edit it.
• Motion editors that match Motion. Easing, cubic-bézier and spring editors; a time-mode spring (visualDuration, bounce) resolves exactly as Motion does, and every one hands back a ready transition easing, a sampled linear() for springs.
• Markup mode. [data-twk] elements become controls in place, no script per control.
• CSP-safe. The plot control parses its expressions itself, with no eval or new Function.
• Values back into source. The copy button puts the tuned values on the clipboard as JSON, and AGENTS.md tells a coding agent how to apply them.

Install

npm install tweakit

tweakit is an ES module only. In a CommonJS project, set "type": "module" in package.json, or load it with await import("tweakit"); TypeScript under moduleResolution: node16 needs the same. There, a .cts file imports the types as import type { Schema } from "tweakit" with { "resolution-mode": "import" } (TS1541 without it; nodenext on current TypeScript does without it).

Use

import { tweaks } from "tweakit";
import "tweakit/css";

const panel = tweaks("Card", {
  blur: [24, 0, 100, 1],          // slider
  visible: true,                   // checkbox
  blend: ["normal", "multiply"],   // list
  tint: "#7C5CFF",                 // wide-gamut color picker
});
document.body.append(panel.el);
panel.on((values) => { /* values.blur, values.tint, … */ });

Panels can also come from [data-twk] markup, bound by enhance(). Importing tweakit binds nothing on its own; import tweakit/auto instead (the same API) to bind the page's markup once it has parsed.

In React (or Vue, Svelte, Solid)

The panel isn't a component: create it once in a mount effect, append panel.el to a ref, and destroy it on unmount. params is updated in place, so copy it into state.

import { useEffect, useRef, useState } from "react";
import { tweaks } from "tweakit";
import "tweakit/css";

function Card() {
  const host = useRef(null);
  const [p, setP] = useState({ radius: 18, tint: "#7C5CFF" });
  useEffect(() => {
    const panel = tweaks("Card", { radius: [18, 0, 60, 1], tint: "#7C5CFF" });
    host.current.append(panel.el);
    panel.on((values) => setP({ ...values }));
    return () => panel.destroy();
  }, []);
  return (<><div ref={host} /><div style={{ borderRadius: p.radius, background: p.tint }} /></>);
}

Gate it behind a development flag (import.meta.env.DEV): tweakit has no production switch of its own.

Everything else is on the docs site: every control live, the panel API, theming, markup-driven panels, and the two builds (the single-file build vs the code-split entry).

Coding agents

Read node_modules/tweakit/AGENTS.md before writing tweakit code. It is the guide for agents (every control and the value it returns, the panel API, how copied values come back), version-matched to the installed package, and also at ryankiley.github.io/tweakit/AGENTS.md. To keep it in reach, add to your project's AGENTS.md or CLAUDE.md:

This project uses tweakit. Explore the code first, then read node_modules/tweakit/AGENTS.md
before writing tweakit code; prefer it over what you remember. Values tuned in a panel arrive
as JSON from its copy button; apply them to the schema defaults in source, not to the panel.

Or hand your agent the whole job:

Install tweakit in this repo. Read https://ryankiley.github.io/tweakit/AGENTS.md first.
Install it with this project's package manager, import "tweakit/css", and add one panel with
a few controls to an existing component so I can tune it live. Bind the values to its styles.
Verify the build.

Floating panel

Every panel drags by its header and lifts into a fixed layer on the first drag. Pass floating to start it there (true sits 16px in from the top-left; { x, y } sets the insets), and draggable: false to pin it. A draggable panel with persist remembers where it was dropped. Its placement is plain .twk-panel CSS, so a class of yours overrides it; the panel API page has the recipe.

Develop

npm install
npm run build
npm test

CI runs Node 22. The build works on Node 20+, but the test suite runs under jsdom, which needs Node 22.22, 24.15 or newer.

Contributions welcome; see CONTRIBUTING.md. Report security issues per SECURITY.md.

Credits

Inspired by Tweakpane and dialkit. Toolbar and control icons from Hugeicons; see THIRD-PARTY-NOTICES.md.