Optimize bundle size with tree-shaking

The default culori import comes with the full set of color spaces and functions to let you prototype quickly and with fewer errors.

However, the way color spaces are initialized prevents the library from being tree-shaken, so when you use a bundler such as Webpack or Parcel, the entire Culori library is bundled regardless of what you're actually using.

Using culori/fn

To optimize the bundle size, you can opt into the tree-shakeable version by importing from culori/fn instead of culori:

import {,,} from 'culori/fn';

It works like the default import, with one key difference: none of the color spaces are pre-registered into the library. In fact, if you'd try to parse() a valid CSS color without having registered any color space, you'd get back undefined:

import { parse } from 'culori/fn';

// ⇒ undefined

Instead, you need to import the definitions of the color spaces you want to support and register them manually with the useMode() method.

Since none of the color spaces are pre-registered the shortcuts to converter(mode), such as culori.rgb or culori.hsl, are also missing. They are, however, helpfully returned by useMode():

import { useMode, modeRgb } from 'culori/fn';

const rgb = useMode(modeRgb);

// ⇒ Object { mode: "rgb", r: 1, g: 0.38823529411764707, b: 0.2784313725490196 }

To recreate a subset of Culori that only deals with valid CSS colors, you would use this:

import {
} from 'culori/fn';

const a98 = useMode(modeA98);
const hsl = useMode(modeHsl);
const hwb = useMode(modeHwb);
const lab = useMode(modeLab);
const lch = useMode(modeLch);
const p3 = useMode(modeP3);
const prophoto = useMode(modeProphoto);
const rec2020 = useMode(modeRec2020);
const rgb = useMode(modeRgb);
const xyz50 = useMode(modeXyz50);
const xyz65 = useMode(modeXyz65);

Using Culori without registering color spaces

You can import and use the low-level parsing and conversion functions without registering any color space beforehand:


import { parseHex, convertRgbToHsl, serializeHsl } from 'culori/fn';

// ⇒ hsl(48, 100%, 50%)

When using a bundler such as esbuild, a minified build fits on the back of a napkin.

Show esbuild output for code above
esbuild --bundle --minify hex-to-hsl-string.js

(()=>{var b=(e,o)=>{if(typeof e=="number"){if(o===3)return{mode:"rgb",r:(e>>8&15|e>>4&240)/255,g:(e>>4&15|e&240)/255,b:(e&15|e<<4&240)/255};if(o===4)return{mode:"rgb",r:(e>>12&15|e>>8&240)/255,g:(e>>8&15|e>>4&240)/255,b:(e>>4&15|e&240)/255,alpha:(e&15|e<<4&240)/255};if(o===6)return{mode:"rgb",r:(e>>16&255)/255,g:(e>>8&255)/255,b:(e&255)/255};if(o===8)return{mode:"rgb",r:(e>>24&255)/255,g:(e>>16&255)/255,b:(e>>8&255)/255,alpha:(e&255)/255}}},u=b;var c=/^#?([0-9a-f]{8}|[0-9a-f]{6}|[0-9a-f]{4}|[0-9a-f]{3})$/i,x=e=>{let o;return(o=e.match(c))?u(parseInt(o[1],16),o[1].length):void 0},l=x;function f({r:e,g:o,b:t,alpha:s}){let r=Math.max(e,o,t),a=Math.min(e,o,t),i={mode:"hsl",s:r===a?0:(r-a)/(1-Math.abs(r+a-1)),l:.5*(r+a)};return r-a!=0&&(i.h=(r===e?(o-t)/(r-a)+(o<t)*6:r===o?(t-e)/(r-a)+2:(e-o)/(r-a)+4)60),s!==void 0&&(i.alpha=s),i}function p(e=4){return o=>typeof o=="number"?Math.round(o(e=Math.pow(10,e)))/e:o}var n=p(2),d=e=>Math.max(0,Math.min(1,e));var m=e=>{if(e===void 0)return;let o=n(e.h||0),t=n(d(e.s)*100),s=n(d(e.l)*100);return e.alpha===void 0||e.alpha===1?hsl(${o}, ${t}%, ${s}%):hsla(${o}, ${t}%, ${s}%, ${n(d(e.alpha))})};console.log(m(f(l("#ffcc00"))));})();

Bootstrap packages

For convenience, a couple of bootstrap packages are available.


Bootstrap all the color spaces available in CSS, plus a handful of related ones we get for free, since they are used under the hood.

It provides the following named exports: a98, hsl, hsv, hwb, lab, lab65, lch, lch65, lrgb, p3, prophoto, rec2020, rgb, xyz50, and xyz65.

import 'culori/css';
import { interpolate } from 'culori/fn';

interpolate(['red', 'green'], 'lch');


Bootstrap all the color spaces available in Culori.

It provides the following named exports: a98, cubehelix, dlab, dlch, hsi, hsl, hsv, hwb, jab, jch, lab, lab65, lch, lch65, lchuv, lrgb, luv, okhsl, okhsv, oklab, oklch, p3, prophoto, rec2020, rgb, xyz50, xyz65, and yiq.

import 'culori/all';
import { interpolate } from 'culori/fn';

interpolate(['red', 'green'], 'oklab');