chore: simplify package entry + test path construction

- restore `main`, drop the `exports` map and `prepare`/tsc build step
- comment the value-parser `word` re-tag in transformValue
- use `new URL(...)` for corpus paths instead of dirname/join chains

Author: dkryaklin

package.json

@@ -14,21 +14,14 @@
     "type": "git",
     "url": "https://github.com/postcss/postcss-calc.git"
   },
+  "main": "src/index.js",
   "types": "types/index.d.ts",
-  "exports": {
-    ".": {
-      "types": "./types/index.d.ts",
-      "default": "./src/index.js"
-    },
-    "./package.json": "./package.json"
-  },
   "files": [
     "src",
     "types",
     "LICENSE"
   ],
   "scripts": {
-    "prepare": "tsc",
     "lint": "eslint . && tsc",
     "test": "node --test",
     "test:mutation": "stryker run",

src/index.js

@@ -67,6 +67,8 @@ function transformValue(value, options, result, item) {
           });
         }
 
+        // Re-tag as `word` so value-parser emits `str` verbatim instead of
+        // re-wrapping it as `name(...)`. Cast widens the `'function'` literal.
         /** @type {{type: string}} */ (node).type = 'word';
         node.value = str;
       } catch (error) {

test/conformance/corpus.test.mjs

@@ -10,13 +10,13 @@
 // assert they agree. Any divergence is either a real bug or a known
 // design choice documented in `KNOWN_DIVERGENCES`.
 import { readdirSync, readFileSync } from 'node:fs';
-import { dirname, join } from 'node:path';
+import { join } from 'node:path';
 import { fileURLToPath } from 'node:url';
 import { test } from 'node:test';
 import assert from 'node:assert/strict';
 import { calc as csstoolsCalc } from '@csstools/css-calc';
 import { out } from '../helpers/out.mjs';
-const CORPUS_DIR = join(dirname(fileURLToPath(import.meta.url)), '../corpus');
+const CORPUS_DIR = fileURLToPath(new URL('../corpus/', import.meta.url));
 const COMPARE_PRECISION = 10;
 function ourOut(input) {
   try {

test/conformance/invalid-corpus.test.mjs

@@ -10,19 +10,12 @@
 //
 // Goal: every input must throw a real synchronous `Error`. No hangs, no
 // non-Error throws.
-import { dirname, join } from 'node:path';
 import { fileURLToPath } from 'node:url';
 import { test } from 'node:test';
 import assert from 'node:assert/strict';
 import { runCorpus, assertResilience } from '../helpers/resilience.mjs';
 const r = runCorpus(
-  join(
-    dirname(fileURLToPath(import.meta.url)),
-    '..',
-    'corpus',
-    'github',
-    'invalid.txt'
-  )
+  fileURLToPath(new URL('../corpus/github/invalid.txt', import.meta.url))
 );
 test(`invalid corpus: ${r.total} expressions parse-or-throw cleanly`, () => {
   assertResilience(r, 'invalid', assert);

test/conformance/preprocessor-corpus.test.mjs

@@ -1,19 +1,12 @@
 // Parser-only resilience test against real-world preprocessor (SCSS/Less)
 // `calc(...)` expressions harvested from public GitHub repos. Asserts every
 // input parses or throws cleanly — no hangs, no non-Error throws.
-import { dirname, join } from 'node:path';
 import { fileURLToPath } from 'node:url';
 import { test } from 'node:test';
 import assert from 'node:assert/strict';
 import { runCorpus, assertResilience } from '../helpers/resilience.mjs';
 const r = runCorpus(
-  join(
-    dirname(fileURLToPath(import.meta.url)),
-    '..',
-    'corpus',
-    'github',
-    'preprocessor.txt'
-  )
+  fileURLToPath(new URL('../corpus/github/preprocessor.txt', import.meta.url))
 );
 test(`preprocessor corpus: ${r.total} expressions parse-or-throw cleanly`, () => {
   assertResilience(r, 'preprocessor', assert);