From 9d309c23f150b94c38bc5e33162f367d289a8916 Mon Sep 17 00:00:00 2001
From: Ludovico Fischer <livrerie@gmail.com>
Date: Tue, 4 Aug 2026 10:54:23 +0200
Subject: [PATCH] refactor: convert to ESM modules

CJS offers no advantage as postcss-calc depends an ESM-only package,
and all Node.js releases that can require() ESM can also run ESM directly.
---
 package.json                             |  1 +
 src/index.js                             | 17 ++++++-------
 src/lib/convertUnits.js                  |  4 +--
 src/lib/node.js                          |  6 +----
 src/lib/parser.js                        |  7 ++----
 src/lib/serialize.js                     |  6 +----
 src/lib/simplify.js                      | 12 +++------
 src/lib/simplify/abs.js                  |  6 ++---
 src/lib/simplify/atan2.js                | 12 ++++-----
 src/lib/simplify/bucket.js               | 15 ++++++-----
 src/lib/simplify/call.js                 | 32 +++++++++++-------------
 src/lib/simplify/cancel.js               |  6 ++---
 src/lib/simplify/clamp.js                |  8 +++---
 src/lib/simplify/exp.js                  |  6 ++---
 src/lib/simplify/fold.js                 | 10 ++------
 src/lib/simplify/hypot.js                |  8 +++---
 src/lib/simplify/inverse-trig.js         |  6 ++---
 src/lib/simplify/log.js                  |  6 ++---
 src/lib/simplify/min-max.js              |  8 +++---
 src/lib/simplify/mod-rem.js              |  8 +++---
 src/lib/simplify/pow.js                  |  6 ++---
 src/lib/simplify/product.js              |  8 +++---
 src/lib/simplify/round.js                |  8 +++---
 src/lib/simplify/sign.js                 |  6 ++---
 src/lib/simplify/sqrt.js                 |  7 ++----
 src/lib/simplify/sum.js                  | 10 +++-----
 src/lib/simplify/trig.js                 |  8 +++---
 src/lib/tokenizer.js                     | 17 ++++---------
 test/{convertUnit.js => convertUnit.cjs} |  0
 test/{index.js => index.cjs}             |  0
 types/index.d.ts                         | 13 ++++++++--
 types/lib/node.d.ts                      | 11 +-------
 types/lib/parser.d.ts                    |  5 +---
 types/lib/serialize.d.ts                 |  5 +---
 types/lib/simplify.d.ts                  |  5 +---
 types/lib/simplify/abs.d.ts              |  5 +---
 types/lib/simplify/atan2.d.ts            |  5 +---
 types/lib/simplify/bucket.d.ts           |  5 +---
 types/lib/simplify/call.d.ts             |  5 +---
 types/lib/simplify/cancel.d.ts           |  5 +---
 types/lib/simplify/clamp.d.ts            |  5 +---
 types/lib/simplify/exp.d.ts              |  5 +---
 types/lib/simplify/fold.d.ts             |  5 +---
 types/lib/simplify/hypot.d.ts            |  5 +---
 types/lib/simplify/inverse-trig.d.ts     |  5 +---
 types/lib/simplify/log.d.ts              |  5 +---
 types/lib/simplify/min-max.d.ts          |  5 +---
 types/lib/simplify/mod-rem.d.ts          |  5 +---
 types/lib/simplify/pow.d.ts              |  5 +---
 types/lib/simplify/product.d.ts          |  5 +---
 types/lib/simplify/round.d.ts            |  5 +---
 types/lib/simplify/sign.d.ts             |  5 +---
 types/lib/simplify/sqrt.d.ts             |  5 +---
 types/lib/simplify/sum.d.ts              |  5 +---
 types/lib/simplify/trig.d.ts             |  5 +---
 types/lib/tokenizer.d.ts                 |  5 +---
 56 files changed, 128 insertions(+), 270 deletions(-)
 rename test/{convertUnit.js => convertUnit.cjs} (100%)
 rename test/{index.js => index.cjs} (100%)

diff --git a/package.json b/package.json
index 1a1b890..a8781cd 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,7 @@
 {
   "name": "postcss-calc",
   "version": "11.0.0-rc.1",
+  "type": "module",
   "description": "PostCSS plugin to reduce calc()",
   "keywords": [
     "css",
diff --git a/src/index.js b/src/index.js
index 5001c5e..2f45952 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,15 +1,11 @@
-'use strict';
-
 // PostCSS adapter. Walks declaration values (and optionally @rule params
 // and selectors), feeds calc() bodies through tokenize → parse → simplify
 // → serialize, and writes the result back.
-
-const valueParser = require('postcss-value-parser');
-
-const { tokenize } = require('./lib/tokenizer.js');
-const { parse } = require('./lib/parser.js');
-const { simplify } = require('./lib/simplify.js');
-const { serialize } = require('./lib/serialize.js');
+import valueParser from 'postcss-value-parser';
+import { tokenize } from './lib/tokenizer.js';
+import { parse } from './lib/parser.js';
+import { simplify } from './lib/simplify.js';
+import { serialize } from './lib/serialize.js';
 
 const MATCH_CALC = /^(?:-(?:moz|webkit)-)?calc$/i;
 
@@ -165,6 +161,7 @@ function pluginCreator(opts) {
 
 pluginCreator.postcss = true;
 
-module.exports = /** @type import('postcss').PluginCreator<PluginOptions>*/ (
+export default /** @type import('postcss').PluginCreator<PluginOptions>*/ (
   pluginCreator
 );
+export { pluginCreator as 'module.exports' };
diff --git a/src/lib/convertUnits.js b/src/lib/convertUnits.js
index 0d55b8f..2093d42 100644
--- a/src/lib/convertUnits.js
+++ b/src/lib/convertUnits.js
@@ -1,5 +1,3 @@
-'use strict';
-
 // Spec: https://www.w3.org/TR/css-values-4/#calc-type-checking
 
 /**
@@ -141,4 +139,4 @@ function convert(value, from, to) {
   return (value * f) / t;
 }
 
-module.exports = { baseOf, convert };
+export { baseOf, convert };
diff --git a/src/lib/node.js b/src/lib/node.js
index 17e46b6..8685888 100644
--- a/src/lib/node.js
+++ b/src/lib/node.js
@@ -1,5 +1,3 @@
-'use strict';
-
 // Canonical AST. N-ary Sum and Product with signed numeric leaves.
 // Invariants enforced by the constructors below:
 //
@@ -184,6 +182,4 @@ function negate(node) {
   return { type: 'Sum', terms: [{ sign: -1, node }] };
 }
 
-// Stryker disable next-line all: instrumenting this line breaks Node's
-// cjs-module-lexer named-export detection for .mjs `import { x } from` consumers.
-module.exports = { num, dim, ident, call, mkSum, mkProduct, negate };
+export { num, dim, ident, call, mkSum, mkProduct, negate };
diff --git a/src/lib/parser.js b/src/lib/parser.js
index f0e8d56..66f309c 100644
--- a/src/lib/parser.js
+++ b/src/lib/parser.js
@@ -1,10 +1,7 @@
-'use strict';
-
 // Pratt parser. +/- emit Sum nodes; */÷ emit Product nodes. node.js
 // constructors flatten and normalize on construction, so the parser
 // never produces a Binary node.
-
-const { mkSum, mkProduct, negate } = require('./node.js');
+import { mkSum, mkProduct, negate } from './node.js';
 
 /**
  * @typedef {import('./tokenizer.js').Token} Token
@@ -318,4 +315,4 @@ function parse(tokens) {
   return ast;
 }
 
-module.exports = { parse };
+export { parse };
diff --git a/src/lib/serialize.js b/src/lib/serialize.js
index dc4335d..5046dbe 100644
--- a/src/lib/serialize.js
+++ b/src/lib/serialize.js
@@ -1,5 +1,3 @@
-'use strict';
-
 // Spec: https://www.w3.org/TR/css-values-4/#serialize-a-calculation-tree
 // Outer calc() is added only when the top-level result contains an
 // arithmetic operator. A Sum inside a Product is the only place parens
@@ -241,6 +239,4 @@ function serializeProduct(product, prec) {
   return out;
 }
 
-// Stryker disable next-line all: instrumenting this line breaks Node's
-// cjs-module-lexer named-export detection for .mjs `import { x } from` consumers.
-module.exports = { serialize };
+export { serialize };
diff --git a/src/lib/simplify.js b/src/lib/simplify.js
index c4f89dc..2bda68b 100644
--- a/src/lib/simplify.js
+++ b/src/lib/simplify.js
@@ -1,12 +1,10 @@
-'use strict';
-
 // Spec: https://www.w3.org/TR/css-values-4/#calc-simplification
 // One top-down pass over a canonical AST. Per-concern fold modules in
 // ./simplify/; this file is the entry + dispatch only.
 
-const { simplifySum } = require('./simplify/sum.js');
-const { simplifyProduct } = require('./simplify/product.js');
-const { simplifyCall } = require('./simplify/call.js');
+import { simplifySum } from './simplify/sum.js';
+import { simplifyProduct } from './simplify/product.js';
+import { simplifyCall } from './simplify/call.js';
 
 /**
  * @typedef {import('./node.js').Node} Node
@@ -35,6 +33,4 @@ function simplify(node) {
   }
 }
 
-// Stryker disable next-line all: instrumenting this line breaks Node's
-// cjs-module-lexer named-export detection for .mjs `import { x } from` consumers.
-module.exports = { simplify };
+export { simplify };
diff --git a/src/lib/simplify/abs.js b/src/lib/simplify/abs.js
index a0d5c6b..65138e2 100644
--- a/src/lib/simplify/abs.js
+++ b/src/lib/simplify/abs.js
@@ -1,6 +1,4 @@
-'use strict';
-
-const { num, dim } = require('../node.js');
+import { num, dim } from '../node.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -22,4 +20,4 @@ function simplifyAbs(args) {
   return { type: 'Call', name: 'abs', args: [a] };
 }
 
-module.exports = { simplifyAbs };
+export { simplifyAbs };
diff --git a/src/lib/simplify/atan2.js b/src/lib/simplify/atan2.js
index 10cef4f..3b7fe2c 100644
--- a/src/lib/simplify/atan2.js
+++ b/src/lib/simplify/atan2.js
@@ -1,10 +1,8 @@
-'use strict';
+/* §10.4 — atan2. foldConstArgs already rejects percentages (property-
+ context-resolved) and enforces shared base + static convertibility. */
 
-// §10.4 — atan2. foldConstArgs already rejects percentages (property-
-// context-resolved) and enforces shared base + static convertibility.
-
-const { num, dim } = require('../node.js');
-const { foldConstArgs } = require('./fold.js');
+import { num, dim } from '../node.js';
+import { foldConstArgs } from './fold.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -28,4 +26,4 @@ function simplifyAtan2(args) {
   return dim((radians * 180) / Math.PI, 'deg');
 }
 
-module.exports = { simplifyAtan2 };
+export { simplifyAtan2 };
diff --git a/src/lib/simplify/bucket.js b/src/lib/simplify/bucket.js
index a066935..05315fa 100644
--- a/src/lib/simplify/bucket.js
+++ b/src/lib/simplify/bucket.js
@@ -1,11 +1,10 @@
-'use strict';
-
-// §10.10 phase 2: merge convertible same-base unit buckets into the
-// first-encountered unit (px absorbs cm/in/pt/pc, deg absorbs
-// rad/grad/turn, …). Buckets with `base === null` (relative or unknown
-// units) keep their own slot.
+/* §10.10 phase 2: merge convertible same-base unit buckets into the
+   first-encountered unit (px absorbs cm/in/pt/pc, deg absorbs
+   rad/grad/turn, …). Buckets with `base === null` (relative or unknown
+   units) keep their own slot.
+ */
 
-const { convert } = require('../convertUnits.js');
+import { convert } from '../convertUnits.js';
 
 /**
  * @typedef {object} UnitBucket
@@ -52,4 +51,4 @@ function mergeConvertibleBuckets(buckets) {
   return out;
 }
 
-module.exports = { mergeConvertibleBuckets };
+export { mergeConvertibleBuckets };
diff --git a/src/lib/simplify/call.js b/src/lib/simplify/call.js
index 56ca639..d4d931c 100644
--- a/src/lib/simplify/call.js
+++ b/src/lib/simplify/call.js
@@ -1,22 +1,20 @@
-'use strict';
-
 // Pre-simplify args once, route by name. Leaf folds receive simplified
 // args so they don't need to recurse into `simplify` themselves.
 
-const { simplifyMinMax } = require('./min-max.js');
-const { simplifyClamp } = require('./clamp.js');
-const { simplifyAbs } = require('./abs.js');
-const { simplifySign } = require('./sign.js');
-const { simplifyModRem } = require('./mod-rem.js');
-const { simplifyRound } = require('./round.js');
-const { simplifyTrig } = require('./trig.js');
-const { simplifyInverseTrig } = require('./inverse-trig.js');
-const { simplifyAtan2 } = require('./atan2.js');
-const { simplifyPow } = require('./pow.js');
-const { simplifySqrt } = require('./sqrt.js');
-const { simplifyExp } = require('./exp.js');
-const { simplifyLog } = require('./log.js');
-const { simplifyHypot } = require('./hypot.js');
+import { simplifyMinMax } from './min-max.js';
+import { simplifyClamp } from './clamp.js';
+import { simplifyAbs } from './abs.js';
+import { simplifySign } from './sign.js';
+import { simplifyModRem } from './mod-rem.js';
+import { simplifyRound } from './round.js';
+import { simplifyTrig } from './trig.js';
+import { simplifyInverseTrig } from './inverse-trig.js';
+import { simplifyAtan2 } from './atan2.js';
+import { simplifyPow } from './pow.js';
+import { simplifySqrt } from './sqrt.js';
+import { simplifyExp } from './exp.js';
+import { simplifyLog } from './log.js';
+import { simplifyHypot } from './hypot.js';
 
 /** @typedef {import('../node.js').Node} Node */
 /** @typedef {import('../simplify.js').SimplifyFn} SimplifyFn */
@@ -84,4 +82,4 @@ function simplifyCall(node, simplify) {
   return { type: 'Call', name: node.name, args };
 }
 
-module.exports = { simplifyCall };
+export { simplifyCall };
diff --git a/src/lib/simplify/cancel.js b/src/lib/simplify/cancel.js
index 9bf4e7b..c6e8942 100644
--- a/src/lib/simplify/cancel.js
+++ b/src/lib/simplify/cancel.js
@@ -1,6 +1,4 @@
-'use strict';
-
-const { baseOf, convert } = require('../convertUnits.js');
+import { baseOf, convert } from '../convertUnits.js';
 
 /**
  * If `dims` contain exactly one numerator / one denominator pair with the
@@ -36,4 +34,4 @@ function tryCancelPair(dims) {
   return { factor: converted / denominator.value, remaining: [] };
 }
 
-module.exports = { tryCancelPair };
+export { tryCancelPair };
diff --git a/src/lib/simplify/clamp.js b/src/lib/simplify/clamp.js
index 66992b5..ee51514 100644
--- a/src/lib/simplify/clamp.js
+++ b/src/lib/simplify/clamp.js
@@ -1,7 +1,5 @@
-'use strict';
-
-const { num, dim } = require('../node.js');
-const { foldConstArgs } = require('./fold.js');
+import { num, dim } from '../node.js';
+import { foldConstArgs } from './fold.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -23,4 +21,4 @@ function simplifyClamp(args) {
   return { type: 'Call', name: 'clamp', args };
 }
 
-module.exports = { simplifyClamp };
+export { simplifyClamp };
diff --git a/src/lib/simplify/exp.js b/src/lib/simplify/exp.js
index 1261714..c7e6817 100644
--- a/src/lib/simplify/exp.js
+++ b/src/lib/simplify/exp.js
@@ -1,6 +1,4 @@
-'use strict';
-
-const { num } = require('../node.js');
+import { num } from '../node.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -15,4 +13,4 @@ function simplifyExp(args) {
   return num(Math.exp(args[0].value));
 }
 
-module.exports = { simplifyExp };
+export { simplifyExp };
diff --git a/src/lib/simplify/fold.js b/src/lib/simplify/fold.js
index a911780..d9ee553 100644
--- a/src/lib/simplify/fold.js
+++ b/src/lib/simplify/fold.js
@@ -1,10 +1,4 @@
-'use strict';
-
-// Fold args to a common numeric representation if they share a type.
-// Percentages never fold — ordering depends on property-context
-// resolution we don't have. Matches csstools.
-
-const { baseOf, convert } = require('../convertUnits.js');
+import { baseOf, convert } from '../convertUnits.js';
 
 /** @typedef {import('../node.js').Node} Node */
 /** @typedef {import('../convertUnits.js').BaseType} BaseType */
@@ -68,4 +62,4 @@ function foldDimArgs(args, unit, base) {
   return { values, unit };
 }
 
-module.exports = { foldConstArgs };
+export { foldConstArgs };
diff --git a/src/lib/simplify/hypot.js b/src/lib/simplify/hypot.js
index 530b682..2e13c46 100644
--- a/src/lib/simplify/hypot.js
+++ b/src/lib/simplify/hypot.js
@@ -1,9 +1,7 @@
-'use strict';
-
 // §10.5 — hypot. Empty args return null from foldConstArgs naturally.
 
-const { num, dim } = require('../node.js');
-const { foldConstArgs } = require('./fold.js');
+import { num, dim } from '../node.js';
+import { foldConstArgs } from './fold.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -21,4 +19,4 @@ function simplifyHypot(args) {
   return fold.unit === '' ? num(result) : dim(result, fold.unit);
 }
 
-module.exports = { simplifyHypot };
+export { simplifyHypot };
diff --git a/src/lib/simplify/inverse-trig.js b/src/lib/simplify/inverse-trig.js
index 2a5d86e..0b9677b 100644
--- a/src/lib/simplify/inverse-trig.js
+++ b/src/lib/simplify/inverse-trig.js
@@ -1,8 +1,6 @@
-'use strict';
-
 // §10.4 — asin/acos/atan. Bare <number> in, <angle> in degrees out.
 
-const { num, dim } = require('../node.js');
+import { num, dim } from '../node.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -32,4 +30,4 @@ function simplifyInverseTrig(name, args) {
   return dim((radians * 180) / Math.PI, 'deg');
 }
 
-module.exports = { simplifyInverseTrig };
+export { simplifyInverseTrig };
diff --git a/src/lib/simplify/log.js b/src/lib/simplify/log.js
index 7c39e7c..fad084b 100644
--- a/src/lib/simplify/log.js
+++ b/src/lib/simplify/log.js
@@ -1,6 +1,4 @@
-'use strict';
-
-const { num } = require('../node.js');
+import { num } from '../node.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -18,4 +16,4 @@ function simplifyLog(args) {
   return { type: 'Call', name: 'log', args };
 }
 
-module.exports = { simplifyLog };
+export { simplifyLog };
diff --git a/src/lib/simplify/min-max.js b/src/lib/simplify/min-max.js
index ced1f25..080781e 100644
--- a/src/lib/simplify/min-max.js
+++ b/src/lib/simplify/min-max.js
@@ -1,7 +1,5 @@
-'use strict';
-
-const { num, dim } = require('../node.js');
-const { foldConstArgs } = require('./fold.js');
+import { num, dim } from '../node.js';
+import { foldConstArgs } from './fold.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -20,4 +18,4 @@ function simplifyMinMax(name, args) {
   return { type: 'Call', name, args };
 }
 
-module.exports = { simplifyMinMax };
+export { simplifyMinMax };
diff --git a/src/lib/simplify/mod-rem.js b/src/lib/simplify/mod-rem.js
index 3fb4eb0..0d82f18 100644
--- a/src/lib/simplify/mod-rem.js
+++ b/src/lib/simplify/mod-rem.js
@@ -1,7 +1,5 @@
-'use strict';
-
-const { num, dim } = require('../node.js');
-const { foldConstArgs } = require('./fold.js');
+import { num, dim } from '../node.js';
+import { foldConstArgs } from './fold.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -56,4 +54,4 @@ function applyModRem(name, a, b) {
   return a - b * Math.floor(a / b);
 }
 
-module.exports = { simplifyModRem };
+export { simplifyModRem };
diff --git a/src/lib/simplify/pow.js b/src/lib/simplify/pow.js
index 6968588..12e85a4 100644
--- a/src/lib/simplify/pow.js
+++ b/src/lib/simplify/pow.js
@@ -1,8 +1,6 @@
-'use strict';
-
 // §10.5 — pow is <number>-only.
 
-const { num } = require('../node.js');
+import { num } from '../node.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -17,4 +15,4 @@ function simplifyPow(args) {
   return num(Math.pow(args[0].value, args[1].value));
 }
 
-module.exports = { simplifyPow };
+export { simplifyPow };
diff --git a/src/lib/simplify/product.js b/src/lib/simplify/product.js
index 185eb2a..2f05a77 100644
--- a/src/lib/simplify/product.js
+++ b/src/lib/simplify/product.js
@@ -1,7 +1,5 @@
-'use strict';
-
-const { mkSum, mkProduct, num, dim } = require('../node.js');
-const { tryCancelPair } = require('./cancel.js');
+import { mkSum, mkProduct, num, dim } from '../node.js';
+import { tryCancelPair } from './cancel.js';
 
 /**
  * @typedef {import('../node.js').Node} Node
@@ -134,4 +132,4 @@ function simplifyProduct(product, simplify) {
   return mkProduct(factors);
 }
 
-module.exports = { simplifyProduct };
+export { simplifyProduct };
diff --git a/src/lib/simplify/round.js b/src/lib/simplify/round.js
index f86ebe4..e86d22b 100644
--- a/src/lib/simplify/round.js
+++ b/src/lib/simplify/round.js
@@ -1,7 +1,5 @@
-'use strict';
-
-const { num, dim } = require('../node.js');
-const { foldConstArgs } = require('./fold.js');
+import { num, dim } from '../node.js';
+import { foldConstArgs } from './fold.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -124,4 +122,4 @@ function applyRound(strategy, a, b) {
   }
 }
 
-module.exports = { simplifyRound };
+export { simplifyRound };
diff --git a/src/lib/simplify/sign.js b/src/lib/simplify/sign.js
index 1956d32..cfaf7d4 100644
--- a/src/lib/simplify/sign.js
+++ b/src/lib/simplify/sign.js
@@ -1,6 +1,4 @@
-'use strict';
-
-const { num } = require('../node.js');
+import { num } from '../node.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -23,4 +21,4 @@ function simplifySign(args) {
   return { type: 'Call', name: 'sign', args: [a] };
 }
 
-module.exports = { simplifySign };
+export { simplifySign };
diff --git a/src/lib/simplify/sqrt.js b/src/lib/simplify/sqrt.js
index 43e1957..a3febc2 100644
--- a/src/lib/simplify/sqrt.js
+++ b/src/lib/simplify/sqrt.js
@@ -1,9 +1,6 @@
-'use strict';
-
-const { num } = require('../node.js');
+import { num } from '../node.js';
 
 /** @typedef {import('../node.js').Node} Node */
-
 /**
  * @param {Node[]} args
  * @return {Node}
@@ -15,4 +12,4 @@ function simplifySqrt(args) {
   return num(Math.sqrt(args[0].value));
 }
 
-module.exports = { simplifySqrt };
+export { simplifySqrt };
diff --git a/src/lib/simplify/sum.js b/src/lib/simplify/sum.js
index ad65f40..c0b7bba 100644
--- a/src/lib/simplify/sum.js
+++ b/src/lib/simplify/sum.js
@@ -1,8 +1,6 @@
-'use strict';
-
-const { mkSum, num, dim } = require('../node.js');
-const { baseOf } = require('../convertUnits.js');
-const { mergeConvertibleBuckets } = require('./bucket.js');
+import { mkSum, num, dim } from '../node.js';
+import { baseOf } from '../convertUnits.js';
+import { mergeConvertibleBuckets } from './bucket.js';
 
 /**
  * @typedef {import('../node.js').Node} Node
@@ -100,4 +98,4 @@ function simplifySum(sum, simplify) {
   return mkSum(terms);
 }
 
-module.exports = { simplifySum };
+export { simplifySum };
diff --git a/src/lib/simplify/trig.js b/src/lib/simplify/trig.js
index b305c3a..81e3649 100644
--- a/src/lib/simplify/trig.js
+++ b/src/lib/simplify/trig.js
@@ -1,9 +1,7 @@
-'use strict';
-
 // §10.4 — sin/cos/tan. <number> is radians; <angle> dim is converted.
 
-const { num } = require('../node.js');
-const { baseOf, convert } = require('../convertUnits.js');
+import { num } from '../node.js';
+import { baseOf, convert } from '../convertUnits.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -43,4 +41,4 @@ function simplifyTrig(name, args) {
   return num(TRIG_OPS[name](radians));
 }
 
-module.exports = { simplifyTrig };
+export { simplifyTrig };
diff --git a/src/lib/tokenizer.js b/src/lib/tokenizer.js
index a9c01ef..83fe302 100644
--- a/src/lib/tokenizer.js
+++ b/src/lib/tokenizer.js
@@ -1,14 +1,9 @@
-'use strict';
-
 // Folds @csstools/css-tokenizer output into the calc() token subset.
 
-// @csstools/css-tokenizer is ESM-only and this package is CJS. require(esm)
-// must happen at first use, not at module evaluation — a consumer's ESM
-// graph may also link the tokenizer (other csstools plugins do), and a
-// load-time require would hit ERR_REQUIRE_CYCLE_MODULE there.
-/** @type {typeof import('@csstools/css-tokenizer') | undefined} */
-let cssTokenizer;
-
+import {
+  tokenize as tokenizeCss,
+  TokenType as CssType,
+} from '@csstools/css-tokenizer';
 /**
  * @typedef {'number' | 'dimension' | 'ident' | 'punct' | 'eof'} TokenType
  * @typedef {object} Token
@@ -28,8 +23,6 @@ const NUMERIC_RAW = /^[+-]?(?:\d+(?:\.\d+)?|\.\d+)(?:[eE][+-]?\d+)?/;
  * @return {Token[]}
  */
 function tokenize(input) {
-  cssTokenizer ??= require('@csstools/css-tokenizer');
-  const { tokenize: tokenizeCss, TokenType: CssType } = cssTokenizer;
   /** @type {Token[]} */
   const tokens = [];
   let ws = true;
@@ -117,4 +110,4 @@ function tokenize(input) {
   return tokens;
 }
 
-module.exports = { tokenize };
+export { tokenize };
diff --git a/test/convertUnit.js b/test/convertUnit.cjs
similarity index 100%
rename from test/convertUnit.js
rename to test/convertUnit.cjs
diff --git a/test/index.js b/test/index.cjs
similarity index 100%
rename from test/index.js
rename to test/index.cjs
diff --git a/types/index.d.ts b/types/index.d.ts
index 7838aee..65310c8 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -1,5 +1,3 @@
-declare const _exports: import("postcss").PluginCreator<PluginOptions>;
-export = _exports;
 export type PluginOptions = {
     precision?: number | false;
     preserve?: boolean;
@@ -12,3 +10,14 @@ export type PluginOptions = {
     onParseError?: (error: Error, input: string) => void;
 };
 export type ResolvedOptions = Required<Omit<PluginOptions, 'onParseError'>> & Pick<PluginOptions, 'onParseError'>;
+/**
+ * @param {PluginOptions} [opts]
+ * @return {import('postcss').Plugin}
+ */
+declare function pluginCreator(opts?: PluginOptions): import('postcss').Plugin;
+declare namespace pluginCreator {
+    var postcss: boolean;
+}
+declare const _default: import('postcss').PluginCreator<PluginOptions>;
+export default _default;
+export { pluginCreator as 'module.exports' };
diff --git a/types/lib/node.d.ts b/types/lib/node.d.ts
index 3165fa8..8743e8b 100644
--- a/types/lib/node.d.ts
+++ b/types/lib/node.d.ts
@@ -1,13 +1,3 @@
-declare const _exports: {
-    num: typeof num;
-    dim: typeof dim;
-    ident: typeof ident;
-    call: typeof call;
-    mkSum: typeof mkSum;
-    mkProduct: typeof mkProduct;
-    negate: typeof negate;
-};
-export = _exports;
 export type Num = {
     type: 'Num';
     value: number;
@@ -92,3 +82,4 @@ declare function mkProduct(rawFactors: ProductFactor[]): Node;
  * @return {Node}
  */
 declare function negate(node: Node): Node;
+export { num, dim, ident, call, mkSum, mkProduct, negate };
diff --git a/types/lib/parser.d.ts b/types/lib/parser.d.ts
index 57fa565..6ba4889 100644
--- a/types/lib/parser.d.ts
+++ b/types/lib/parser.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    parse: typeof parse;
-};
-export = _exports;
 export type Token = import('./tokenizer.js').Token;
 export type TokenType = import('./tokenizer.js').TokenType;
 export type Node = import('./node.js').Node;
@@ -40,3 +36,4 @@ declare class Parser {
  * @return {Node}
  */
 declare function parse(tokens: Token[]): Node;
+export { parse };
diff --git a/types/lib/serialize.d.ts b/types/lib/serialize.d.ts
index 256968a..f3c408f 100644
--- a/types/lib/serialize.d.ts
+++ b/types/lib/serialize.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    serialize: typeof serialize;
-};
-export = _exports;
 export type Node = import('./node.js').Node;
 export type Sum = import('./node.js').Sum;
 export type Product = import('./node.js').Product;
@@ -22,3 +18,4 @@ export type SerializeOptions = {
  * @return {string}
  */
 declare function serialize(node: Node, opts?: SerializeOptions): string;
+export { serialize };
diff --git a/types/lib/simplify.d.ts b/types/lib/simplify.d.ts
index 661e870..9e8f9bb 100644
--- a/types/lib/simplify.d.ts
+++ b/types/lib/simplify.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplify: typeof simplify;
-};
-export = _exports;
 export type Node = import('./node.js').Node;
 export type SimplifyFn = (node: Node) => Node;
 /**
@@ -16,3 +12,4 @@ export type SimplifyFn = (node: Node) => Node;
  * @return {Node}
  */
 declare function simplify(node: Node): Node;
+export { simplify };
diff --git a/types/lib/simplify/abs.d.ts b/types/lib/simplify/abs.d.ts
index 6ce5bed..b68cadb 100644
--- a/types/lib/simplify/abs.d.ts
+++ b/types/lib/simplify/abs.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplifyAbs: typeof simplifyAbs;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 /** @typedef {import('../node.js').Node} Node */
 /**
@@ -9,3 +5,4 @@ export type Node = import('../node.js').Node;
  * @return {Node}
  */
 declare function simplifyAbs(args: Node[]): Node;
+export { simplifyAbs };
diff --git a/types/lib/simplify/atan2.d.ts b/types/lib/simplify/atan2.d.ts
index 3841b67..e6da885 100644
--- a/types/lib/simplify/atan2.d.ts
+++ b/types/lib/simplify/atan2.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplifyAtan2: typeof simplifyAtan2;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 /** @typedef {import('../node.js').Node} Node */
 /**
@@ -9,3 +5,4 @@ export type Node = import('../node.js').Node;
  * @return {Node}
  */
 declare function simplifyAtan2(args: Node[]): Node;
+export { simplifyAtan2 };
diff --git a/types/lib/simplify/bucket.d.ts b/types/lib/simplify/bucket.d.ts
index 9f72f37..1026514 100644
--- a/types/lib/simplify/bucket.d.ts
+++ b/types/lib/simplify/bucket.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    mergeConvertibleBuckets: typeof mergeConvertibleBuckets;
-};
-export = _exports;
 export type UnitBucket = {
     unit: string;
     total: number;
@@ -26,3 +22,4 @@ export type UnitBucket = {
  * @return {UnitBucket[]}
  */
 declare function mergeConvertibleBuckets(buckets: UnitBucket[]): UnitBucket[];
+export { mergeConvertibleBuckets };
diff --git a/types/lib/simplify/call.d.ts b/types/lib/simplify/call.d.ts
index 8029aa5..3f1e66f 100644
--- a/types/lib/simplify/call.d.ts
+++ b/types/lib/simplify/call.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplifyCall: typeof simplifyCall;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 export type SimplifyFn = import('../simplify.js').SimplifyFn;
 /** @typedef {import('../node.js').Node} Node */
@@ -14,3 +10,4 @@ export type SimplifyFn = import('../simplify.js').SimplifyFn;
 declare function simplifyCall(node: Extract<Node, {
     type: 'Call';
 }>, simplify: SimplifyFn): Node;
+export { simplifyCall };
diff --git a/types/lib/simplify/cancel.d.ts b/types/lib/simplify/cancel.d.ts
index 2a3b3b6..81c47b9 100644
--- a/types/lib/simplify/cancel.d.ts
+++ b/types/lib/simplify/cancel.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    tryCancelPair: typeof tryCancelPair;
-};
-export = _exports;
 /**
  * If `dims` contain exactly one numerator / one denominator pair with the
  * same base type and convertible units, return the numeric factor produced
@@ -21,3 +17,4 @@ declare function tryCancelPair<D extends {
     factor: number;
     remaining: D[];
 } | null;
+export { tryCancelPair };
diff --git a/types/lib/simplify/clamp.d.ts b/types/lib/simplify/clamp.d.ts
index e21bab3..7643f82 100644
--- a/types/lib/simplify/clamp.d.ts
+++ b/types/lib/simplify/clamp.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplifyClamp: typeof simplifyClamp;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 /** @typedef {import('../node.js').Node} Node */
 /**
@@ -9,3 +5,4 @@ export type Node = import('../node.js').Node;
  * @return {Node}
  */
 declare function simplifyClamp(args: Node[]): Node;
+export { simplifyClamp };
diff --git a/types/lib/simplify/exp.d.ts b/types/lib/simplify/exp.d.ts
index bf1d90a..f81f36c 100644
--- a/types/lib/simplify/exp.d.ts
+++ b/types/lib/simplify/exp.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplifyExp: typeof simplifyExp;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 /** @typedef {import('../node.js').Node} Node */
 /**
@@ -9,3 +5,4 @@ export type Node = import('../node.js').Node;
  * @return {Node}
  */
 declare function simplifyExp(args: Node[]): Node;
+export { simplifyExp };
diff --git a/types/lib/simplify/fold.d.ts b/types/lib/simplify/fold.d.ts
index 9733ff4..7cf2327 100644
--- a/types/lib/simplify/fold.d.ts
+++ b/types/lib/simplify/fold.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    foldConstArgs: typeof foldConstArgs;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 export type BaseType = import('../convertUnits.js').BaseType;
 /** @typedef {import('../node.js').Node} Node */
@@ -14,3 +10,4 @@ declare function foldConstArgs(args: Node[]): {
     values: number[];
     unit: string;
 } | null;
+export { foldConstArgs };
diff --git a/types/lib/simplify/hypot.d.ts b/types/lib/simplify/hypot.d.ts
index ec0f94e..6fd2405 100644
--- a/types/lib/simplify/hypot.d.ts
+++ b/types/lib/simplify/hypot.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplifyHypot: typeof simplifyHypot;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 /** @typedef {import('../node.js').Node} Node */
 /**
@@ -9,3 +5,4 @@ export type Node = import('../node.js').Node;
  * @return {Node}
  */
 declare function simplifyHypot(args: Node[]): Node;
+export { simplifyHypot };
diff --git a/types/lib/simplify/inverse-trig.d.ts b/types/lib/simplify/inverse-trig.d.ts
index 6c19317..2540422 100644
--- a/types/lib/simplify/inverse-trig.d.ts
+++ b/types/lib/simplify/inverse-trig.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplifyInverseTrig: typeof simplifyInverseTrig;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 /**
  * @param {'asin' | 'acos' | 'atan'} name
@@ -9,3 +5,4 @@ export type Node = import('../node.js').Node;
  * @return {Node}
  */
 declare function simplifyInverseTrig(name: 'asin' | 'acos' | 'atan', args: Node[]): Node;
+export { simplifyInverseTrig };
diff --git a/types/lib/simplify/log.d.ts b/types/lib/simplify/log.d.ts
index cb8c3ac..dc63a1f 100644
--- a/types/lib/simplify/log.d.ts
+++ b/types/lib/simplify/log.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplifyLog: typeof simplifyLog;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 /** @typedef {import('../node.js').Node} Node */
 /**
@@ -9,3 +5,4 @@ export type Node = import('../node.js').Node;
  * @return {Node}
  */
 declare function simplifyLog(args: Node[]): Node;
+export { simplifyLog };
diff --git a/types/lib/simplify/min-max.d.ts b/types/lib/simplify/min-max.d.ts
index 9f02472..bd75d6b 100644
--- a/types/lib/simplify/min-max.d.ts
+++ b/types/lib/simplify/min-max.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplifyMinMax: typeof simplifyMinMax;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 /** @typedef {import('../node.js').Node} Node */
 /**
@@ -10,3 +6,4 @@ export type Node = import('../node.js').Node;
  * @return {Node}
  */
 declare function simplifyMinMax(name: string, args: Node[]): Node;
+export { simplifyMinMax };
diff --git a/types/lib/simplify/mod-rem.d.ts b/types/lib/simplify/mod-rem.d.ts
index fa8ed6c..aebaa42 100644
--- a/types/lib/simplify/mod-rem.d.ts
+++ b/types/lib/simplify/mod-rem.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplifyModRem: typeof simplifyModRem;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 /** @typedef {import('../node.js').Node} Node */
 /**
@@ -10,3 +6,4 @@ export type Node = import('../node.js').Node;
  * @return {Node}
  */
 declare function simplifyModRem(name: 'mod' | 'rem', args: Node[]): Node;
+export { simplifyModRem };
diff --git a/types/lib/simplify/pow.d.ts b/types/lib/simplify/pow.d.ts
index 1425a82..a53c7e0 100644
--- a/types/lib/simplify/pow.d.ts
+++ b/types/lib/simplify/pow.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplifyPow: typeof simplifyPow;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 /** @typedef {import('../node.js').Node} Node */
 /**
@@ -9,3 +5,4 @@ export type Node = import('../node.js').Node;
  * @return {Node}
  */
 declare function simplifyPow(args: Node[]): Node;
+export { simplifyPow };
diff --git a/types/lib/simplify/product.d.ts b/types/lib/simplify/product.d.ts
index 7de35d4..d00e66b 100644
--- a/types/lib/simplify/product.d.ts
+++ b/types/lib/simplify/product.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplifyProduct: typeof simplifyProduct;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 export type Product = import('../node.js').Product;
 export type ProductFactor = import('../node.js').ProductFactor;
@@ -18,3 +14,4 @@ export type SimplifyFn = import('../simplify.js').SimplifyFn;
  * @return {Node}
  */
 declare function simplifyProduct(product: Product, simplify: SimplifyFn): Node;
+export { simplifyProduct };
diff --git a/types/lib/simplify/round.d.ts b/types/lib/simplify/round.d.ts
index 401b563..d2b40ec 100644
--- a/types/lib/simplify/round.d.ts
+++ b/types/lib/simplify/round.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplifyRound: typeof simplifyRound;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 export type RoundStrategy = 'nearest' | 'up' | 'down' | 'to-zero';
 /** @typedef {'nearest' | 'up' | 'down' | 'to-zero'} RoundStrategy */
@@ -10,3 +6,4 @@ export type RoundStrategy = 'nearest' | 'up' | 'down' | 'to-zero';
  * @return {Node}
  */
 declare function simplifyRound(args: Node[]): Node;
+export { simplifyRound };
diff --git a/types/lib/simplify/sign.d.ts b/types/lib/simplify/sign.d.ts
index 6f5184c..18664e2 100644
--- a/types/lib/simplify/sign.d.ts
+++ b/types/lib/simplify/sign.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplifySign: typeof simplifySign;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 /** @typedef {import('../node.js').Node} Node */
 /**
@@ -9,3 +5,4 @@ export type Node = import('../node.js').Node;
  * @return {Node}
  */
 declare function simplifySign(args: Node[]): Node;
+export { simplifySign };
diff --git a/types/lib/simplify/sqrt.d.ts b/types/lib/simplify/sqrt.d.ts
index fa1f40d..17693da 100644
--- a/types/lib/simplify/sqrt.d.ts
+++ b/types/lib/simplify/sqrt.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplifySqrt: typeof simplifySqrt;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 /** @typedef {import('../node.js').Node} Node */
 /**
@@ -9,3 +5,4 @@ export type Node = import('../node.js').Node;
  * @return {Node}
  */
 declare function simplifySqrt(args: Node[]): Node;
+export { simplifySqrt };
diff --git a/types/lib/simplify/sum.d.ts b/types/lib/simplify/sum.d.ts
index c40a922..0623654 100644
--- a/types/lib/simplify/sum.d.ts
+++ b/types/lib/simplify/sum.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplifySum: typeof simplifySum;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 export type Sum = import('../node.js').Sum;
 export type SumTerm = import('../node.js').SumTerm;
@@ -13,3 +9,4 @@ export type UnitBucket = import('./bucket.js').UnitBucket;
  * @return {Node}
  */
 declare function simplifySum(sum: Sum, simplify: SimplifyFn): Node;
+export { simplifySum };
diff --git a/types/lib/simplify/trig.d.ts b/types/lib/simplify/trig.d.ts
index a9cb25e..8536d43 100644
--- a/types/lib/simplify/trig.d.ts
+++ b/types/lib/simplify/trig.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    simplifyTrig: typeof simplifyTrig;
-};
-export = _exports;
 export type Node = import('../node.js').Node;
 /**
  * @param {'sin' | 'cos' | 'tan'} name
@@ -9,3 +5,4 @@ export type Node = import('../node.js').Node;
  * @return {Node}
  */
 declare function simplifyTrig(name: 'sin' | 'cos' | 'tan', args: Node[]): Node;
+export { simplifyTrig };
diff --git a/types/lib/tokenizer.d.ts b/types/lib/tokenizer.d.ts
index 23e8da4..2675361 100644
--- a/types/lib/tokenizer.d.ts
+++ b/types/lib/tokenizer.d.ts
@@ -1,7 +1,3 @@
-declare const _exports: {
-    tokenize: typeof tokenize;
-};
-export = _exports;
 export type TokenType = 'number' | 'dimension' | 'ident' | 'punct' | 'eof';
 export type Token = {
     type: TokenType;
@@ -21,3 +17,4 @@ export type Token = {
  * @return {Token[]}
  */
 declare function tokenize(input: string): Token[];
+export { tokenize };