postcss 8.5.25

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pkg:npm/postcss@8.5.25
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/postcss@8.5.25
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - runtime: node@22.23.2

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:7050818d06e979d5a263bdb8401bf62409812414f7d2aef0cfebfaa3ff43731e","constraints":{"executionContext":"node"},"contract":["assert postcss.parse parses CSS into an AST Root node containing AtRule, Rule, Declaration, and Comment child nodes","assert root.walkDecls and root.walkRules traverse descendant nodes with optional property or selector name filtering","assert postcss.root, postcss.rule, and postcss.decl construct AST nodes programmatically and serialize into formatted CSS","assert AST mutation methods including clone, replaceWith, remove, and after modify the node tree and update toString output","assert postcss.parse throws CssSyntaxError with line and column information when parsing malformed or unclosed CSS syntax"],"goal":"verify pkg:npm/postcss@8.5.25","kind":"HOW","packages":["pkg:npm/postcss@8.5.25"],"schemaVersion":1},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","os":"linux","osVersionBucket":"24","packageManager":"npm","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/postcss@8.5.25"],"schemaVersion":1,"subject":"pkg:npm/postcss@8.5.25","verifierAdapter":"node-typescript@1"}

{
  "name": "sample-postcss",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-postcss",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "postcss": "8.5.25"
      }
    },
    "node_modules/nanoid": {
      "version": "3.3.18",
      "resolved": "https://registry.npmjs.org/nanoid/-/nanoid-3.3.18.tgz",
      "integrity": "sha512-DTg4MJbGMWkfi6VZFdNt2/caMbQy4Ou+Op/hJQvGEWcnVfoA1QA+xzRKAzw9jD6+GVOOeYr/mIcuDSdug6F6+w==",
      "funding": [
        {
          "type": "github",
          "url": "https://github.com/sponsors/ai"
        }
      ],
      "license": "MIT",
      "bin": {
        "nanoid": "bin/nanoid.cjs"
      },
      "engines": {
        "node": "^10 || ^12 || ^13.7 || ^14 || >=15.0.1"
      }
    },
    "node_modules/picocolors": {
      "version": "1.1.1",
      "resolved": "https://registry.npmjs.org/picocolors/-/picocolors-1.1.1.tgz",
      "integrity": "sha512-xceH2snhtb5M9liqDsmEw56le376mTZkEX/jEb/RxNFyegNul7eNslCXP9FDj/Lcu0X8KEyMceP2ntpaHrDEVA==",
      "license": "ISC"
    },
    "node_modules/postcss": {
      "version": "8.5.25",
      "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.5.25.tgz",
      "integrity": "sha512-DTPx3RWSSnWyzLxQnlH0rJP+EW5ekl16ZU4/psbIhA0e53kJfdgaN5vKM+xP7yJtXVu+nfdVFmlgFDEKAe4Pyw==",
      "funding": [
        {
          "type": "opencollective",
          "url": "https://opencollective.com/postcss/"
        },
        {
          "type": "tidelift",
          "url": "https://tidelift.com/funding/github/npm/postcss"
        },
        {
          "type": "github",
          "url": "https://github.com/sponsors/ai"
        }
      ],
      "license": "MIT",
      "dependencies": {
        "nanoid": "^3.3.16",
        "picocolors": "^1.1.1",
        "source-map-js": "^1.2.1"
      },
      "engines": {
        "node": "^10 || ^12 || >=14"
      }
    },
    "node_modules/source-map-js": {
      "version": "1.2.1",
      "resolved": "https://registry.npmjs.org/source-map-js/-/source-map-js-1.2.1.tgz",
      "integrity": "sha512-UXWMKhLOwVKb728IUtQPXxfYU+usdybtUrK/8uGE8CQMvrhOpwvzDBwj0QhSL7MQc7vIsISBG8VQ8+IDQxpfQA==",
      "license": "BSD-3-Clause",
      "engines": {
        "node": ">=0.10.0"
      }
    }
  }
}

{
  "name": "sample-postcss",
  "version": "1.0.0",
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "postcss": "8.5.25"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/postcss@8.5.25",
  "kind": "HOW",
  "packages": [
    "pkg:npm/postcss@8.5.25"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "runtime": "node@22.23.2"
  }
}

import assert from 'node:assert/strict';
import { createRequire } from 'node:module';

const require = createRequire(import.meta.url);
const postcss = require('postcss');

// 1. assert postcss.parse parses CSS into an AST Root node containing AtRule, Rule, Declaration, and Comment child nodes
{
  const css = `
    /* Navigation header */
    @media screen and (min-width: 768px) {
      .header {
        color: #333333;
        font-size: 16px !important;
      }
    }
  `;
  const root = postcss.parse(css);
  assert.equal(root.type, 'root');
  assert.equal(root.nodes.length, 2);

  const comment = root.nodes[0];
  assert.equal(comment.type, 'comment');
  assert.equal(comment.text, 'Navigation header');

  const atRule = root.nodes[1];
  assert.equal(atRule.type, 'atrule');
  assert.equal(atRule.name, 'media');
  assert.equal(atRule.params, 'screen and (min-width: 768px)');
  assert.equal(atRule.nodes.length, 1);

  const rule = atRule.nodes[0];
  assert.equal(rule.type, 'rule');
  assert.equal(rule.selector, '.header');
  assert.equal(rule.nodes.length, 2);

  const [colorDecl, fontDecl] = rule.nodes;
  assert.equal(colorDecl.type, 'decl');
  assert.equal(colorDecl.prop, 'color');
  assert.equal(colorDecl.value, '#333333');
  assert.equal(Boolean(colorDecl.important), false);

  assert.equal(fontDecl.type, 'decl');
  assert.equal(fontDecl.prop, 'font-size');
  assert.equal(fontDecl.value, '16px');
  assert.equal(fontDecl.important, true);
}

// 2. assert root.walkDecls and root.walkRules traverse descendant nodes with optional property or selector name filtering
{
  const css = `
    .card { color: #111; background: #fff; }
    .footer { color: #222; border: 1px solid #ccc; }
  `;
  const root = postcss.parse(css);

  const colorValues = [];
  root.walkDecls('color', (decl) => {
    colorValues.push(decl.value);
  });
  assert.deepEqual(colorValues, ['#111', '#222']);

  const allProps = [];
  root.walkDecls((decl) => {
    allProps.push(decl.prop);
  });
  assert.deepEqual(allProps, ['color', 'background', 'color', 'border']);

  const rules = [];
  root.walkRules('.card', (rule) => {
    rules.push(rule.selector);
  });
  assert.deepEqual(rules, ['.card']);
}

// 3. assert postcss.root, postcss.rule, and postcss.decl construct AST nodes programmatically and serialize into formatted CSS
{
  const customRoot = postcss.root();
  const rule = postcss.rule({ selector: '.btn-primary' });
  rule.append(postcss.decl({ prop: 'display', value: 'inline-flex' }));
  rule.append(postcss.decl({ prop: 'padding', value: '0.5rem 1rem' }));
  customRoot.append(rule);

  const expectedCss = '.btn-primary {\n    display: inline-flex;\n    padding: 0.5rem 1rem\n}';
  assert.equal(customRoot.toString(), expectedCss);
}

// 4. assert AST mutation methods including clone, replaceWith, remove, and after modify the node tree and update toString output
{
  const css = '.box { margin: 10px; opacity: 0.8; }';
  const root = postcss.parse(css);

  root.walkDecls('margin', (decl) => {
    const cloned = decl.clone({ prop: 'padding', value: '5px' });
    decl.after(cloned);
    decl.replaceWith(postcss.decl({ prop: 'margin', value: '15px' }));
  });

  root.walkDecls('opacity', (decl) => {
    decl.remove();
  });

  const output = root.toString();
  assert.equal(output, '.box { margin: 15px; padding: 5px; }');
}

// 5. assert postcss.parse throws CssSyntaxError with line and column information when parsing malformed or unclosed CSS syntax
{
  assert.throws(
    () => postcss.parse('.unclosed { color: red;'),
    (err) => {
      return (
        err.name === 'CssSyntaxError' &&
        err.reason === 'Unclosed block' &&
        typeof err.line === 'number' &&
        typeof err.column === 'number'
      );
    }
  );
}