postcss 8.5.26: root

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 postcss.root in pkg:npm/postcss@8.5.26
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/postcss@8.5.26
Demonstrate these symbols/APIs:
  - postcss.root

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:a402d7038fcfadd24503029f15469ad79075f9d6811ddad6a7bcf31cac6dffd9","contract":["assert postcss.root initializes an empty Root node or configures child nodes and raw formatting from defaults","assert root.append, root.prepend, root.insertBefore, and root.insertAfter construct and order the AST node hierarchy","assert root.walk, root.walkRules, root.walkDecls, root.walkAtRules, and root.walkComments traverse descendants with type and name filtering and early termination","assert root.toResult processes root AST directly into LazyResult and root.toString serializes CSS with default or custom stringifiers","assert root.clone performs deep AST duplication without mutating the original root and root.cleanRaws resets formatting raws"],"goal":"verify postcss.root in pkg:npm/postcss@8.5.26","kind":"HOW","packages":["pkg:npm/postcss@8.5.26"],"schemaVersion":1,"symbols":["postcss.root"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"npm","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/postcss@8.5.26"],"schemaVersion":1,"subject":"pkg:npm/postcss@8.5.26","symbols":["postcss.root"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-postcss-root",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-postcss-root",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "postcss": "8.5.26"
      }
    },
    "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": "8.5.26",
      "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.5.26.tgz",
      "integrity": "sha512-u82N74LFzG8ca+dD8puPnplTXoGH4fTPpVGuIbt36G3qvNlkvfD0lEAZSxaly3KX8TS/L1A1gsCEmvKmBcVbkQ==",
      "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": "^3.3.17",
        "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-root",
  "version": "1.0.0",
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "postcss": "8.5.26"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify postcss.root in pkg:npm/postcss@8.5.26",
  "kind": "HOW",
  "packages": [
    "pkg:npm/postcss@8.5.26"
  ],
  "symbols": [
    "postcss.root"
  ]
}

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

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

// 1. assert postcss.root initializes an empty Root node or configures child nodes and raw formatting from defaults
{
  const emptyRoot = postcss.root();
  assert.equal(emptyRoot.type, 'root');
  assert.deepEqual(emptyRoot.nodes, []);
  assert.equal(emptyRoot.name, undefined);
  assert.equal(emptyRoot.selector, undefined);
  assert.equal(emptyRoot.first, undefined);
  assert.equal(emptyRoot.last, undefined);

  const initialRule = postcss.rule({ selector: '.box' });
  const rootWithDefaults = postcss.root({
    nodes: [initialRule],
    raws: { after: '\n', indent: '  ' }
  });
  assert.equal(rootWithDefaults.type, 'root');
  assert.equal(rootWithDefaults.nodes.length, 1);
  assert.equal(rootWithDefaults.first, initialRule);
  assert.equal(rootWithDefaults.last, initialRule);
  assert.equal(rootWithDefaults.raws.indent, '  ');
}

// 2. assert root.append, root.prepend, root.insertBefore, and root.insertAfter construct and order the AST node hierarchy
{
  const root = postcss.root();
  const mainRule = postcss.rule({ selector: 'main' });
  mainRule.append(postcss.decl({ prop: 'display', value: 'grid' }));
  root.append(mainRule);

  const headerRule = postcss.rule({ selector: 'header' });
  headerRule.append(postcss.decl({ prop: 'color', value: '#333' }));
  root.prepend(headerRule);

  assert.equal(root.first.selector, 'header');
  assert.equal(root.last.selector, 'main');
  assert.equal(root.nodes.length, 2);

  const comment = postcss.comment({ text: 'navigation' });
  root.insertBefore(mainRule, comment);
  assert.equal(root.nodes[1], comment);
  assert.equal(root.index(comment), 1);

  const footerRule = postcss.rule({ selector: 'footer' });
  root.insertAfter(comment, footerRule);
  assert.equal(root.index(footerRule), 2);
  assert.equal(root.nodes.length, 4);
}

// 3. assert root.walk, root.walkRules, root.walkDecls, root.walkAtRules, and root.walkComments traverse descendants with type and name filtering and early termination
{
  const root = postcss.root();
  const media = postcss.atRule({ name: 'media', params: 'screen and (min-width: 1024px)' });
  const rule = postcss.rule({ selector: '.container' });
  rule.append(postcss.decl({ prop: 'max-width', value: '1200px' }));
  rule.append(postcss.decl({ prop: 'margin', value: '0 auto' }));
  media.append(rule);
  root.append(media);
  root.append(postcss.comment({ text: 'footer note' }));

  const walkedTypes = [];
  root.walk((node) => {
    walkedTypes.push(node.type);
  });
  assert.deepEqual(walkedTypes, ['atrule', 'rule', 'decl', 'decl', 'comment']);

  const declProps = [];
  root.walkDecls((decl) => {
    declProps.push(decl.prop);
  });
  assert.deepEqual(declProps, ['max-width', 'margin']);

  const atRules = [];
  root.walkAtRules('media', (atRule) => {
    atRules.push(atRule.params);
  });
  assert.deepEqual(atRules, ['screen and (min-width: 1024px)']);

  const comments = [];
  root.walkComments((c) => {
    comments.push(c.text);
  });
  assert.deepEqual(comments, ['footer note']);

  let earlyCount = 0;
  root.walkDecls((decl) => {
    earlyCount++;
    return false;
  });
  assert.equal(earlyCount, 1);
}

// 4. assert root.toResult processes root AST directly into LazyResult and root.toString serializes CSS with default or custom stringifiers
{
  const root = postcss.root();
  const rule = postcss.rule({ selector: 'button.btn' });
  rule.append(postcss.decl({ prop: 'background-color', value: 'blue' }));
  rule.append(postcss.decl({ prop: 'border', value: 'none' }));
  root.append(rule);

  const lazyResult = root.toResult({ map: false });
  assert.ok(lazyResult.css);
  assert.equal(lazyResult.root, root);
  assert.equal(lazyResult.css, 'button.btn {\n    background-color: blue;\n    border: none\n}');

  assert.equal(root.toString(), 'button.btn {\n    background-color: blue;\n    border: none\n}');

  const customStringifier = (node, builder) => {
    if (node.type === 'decl') {
      builder(`${node.prop}: ${node.value};`, node);
    } else if (node.type === 'rule') {
      builder(`${node.selector} { `, node, 'start');
      node.nodes.forEach((child) => customStringifier(child, builder));
      builder(' }', node, 'end');
    } else if (node.type === 'root') {
      node.nodes.forEach((child) => customStringifier(child, builder));
    }
  };

  const customCss = root.toString(customStringifier);
  assert.equal(customCss, 'button.btn { background-color: blue;border: none; }');
}

// 5. assert root.clone performs deep AST duplication without mutating the original root and root.cleanRaws resets formatting raws
{
  const root = postcss.root();
  const rule = postcss.rule({ selector: '.card' });
  rule.append(postcss.decl({ prop: 'padding', value: '16px' }));
  root.append(rule);

  const cloned = root.clone({ raws: { after: '\n\n' } });
  assert.notEqual(cloned, root);
  assert.equal(cloned.nodes.length, 1);
  assert.equal(cloned.first.selector, '.card');
  assert.notEqual(cloned.first, root.first);

  cloned.first.append(postcss.decl({ prop: 'color', value: 'red' }));
  assert.equal(root.first.nodes.length, 1);
  assert.equal(cloned.first.nodes.length, 2);

  cloned.cleanRaws();
  assert.equal(cloned.raws.after, undefined);
  assert.equal(cloned.toString(), '.card {\n    padding: 16px;\n    color: red\n}');
}