rrweb-cssom 0.7.1: parse

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 rrweb-cssom.parse in pkg:npm/rrweb-cssom@0.7.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/rrweb-cssom@0.7.1
Demonstrate these symbols/APIs:
  - rrweb-cssom.parse

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:c74d22b3c18ac5abf32825f1a21cc07d55f265bb77dda758121270339df478ef","contract":["assert parse returns a CSSStyleSheet with 0 rules for an empty string","assert parse parses CSS style rules and populates selectorText, style declarations, and parentStyleSheet","assert parse parses multiple CSS rules and ignores comments","assert parse parses @media at-rules and populates nested rules and parentRule","assert parse parses @keyframes at-rules and populates keyframes name and keyText","assert parse parses @import at-rules and populates href and media query","assert extractStyleRules extracts only CSSStyleRule instances from a parsed stylesheet"],"goal":"verify rrweb-cssom.parse in pkg:npm/rrweb-cssom@0.7.1","kind":"HOW","packages":["pkg:npm/rrweb-cssom@0.7.1"],"schemaVersion":1,"symbols":["rrweb-cssom.parse"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"esm","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/rrweb-cssom@0.7.1"],"schemaVersion":1,"subject":"pkg:npm/rrweb-cssom@0.7.1","symbols":["rrweb-cssom.parse"],"verifierAdapter":"node-typescript@1"}

import { parse } from 'rrweb-cssom';

/**
 * Parses CSS text into a CSSStyleSheet AST using rrweb-cssom.
 *
 * @param {string} cssText - Raw CSS stylesheet string.
 * @returns {import('rrweb-cssom').CSSStyleSheet} Parsed CSSStyleSheet object.
 */
export function parseStylesheet(cssText) {
  return parse(cssText);
}

/**
 * Extracts all style rules (CSSStyleRule) from a CSS string.
 *
 * @param {string} cssText - Raw CSS stylesheet string.
 * @returns {Array} List of style rules.
 */
export function extractStyleRules(cssText) {
  const stylesheet = parse(cssText);
  const rules = [];
  for (let i = 0; i < stylesheet.cssRules.length; i++) {
    const rule = stylesheet.cssRules[i];
    if (rule.type === 1 || rule.constructor.name === 'CSSStyleRule') {
      rules.push(rule);
    }
  }
  return rules;
}

export { parse };

{
  "name": "sample-rrweb-cssom-parse",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-rrweb-cssom-parse",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "rrweb-cssom": "0.7.1"
      }
    },
    "node_modules/rrweb-cssom": {
      "version": "0.7.1",
      "resolved": "https://registry.npmjs.org/rrweb-cssom/-/rrweb-cssom-0.7.1.tgz",
      "integrity": "sha512-TrEMa7JGdVm0UThDJSx7ddw5nVm3UJS9o9CCIZ72B1vSyEZoziDqBYP3XIoi/12lKrJR8rE3jeFHMok2F/Mnsg==",
      "license": "MIT"
    }
  }
}

{
  "name": "sample-rrweb-cssom-parse",
  "version": "1.0.0",
  "description": "Clean-room sample verifying rrweb-cssom.parse functionality",
  "type": "module",
  "main": "index.js",
  "license": "MIT-0",
  "dependencies": {
    "rrweb-cssom": "0.7.1"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify rrweb-cssom.parse in pkg:npm/rrweb-cssom@0.7.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/rrweb-cssom@0.7.1"
  ],
  "symbols": [
    "rrweb-cssom.parse"
  ]
}

import assert from 'node:assert';
import { parse } from 'rrweb-cssom';
import { parseStylesheet, extractStyleRules } from '../index.js';

// 1. Empty CSS string returns an empty CSSStyleSheet
const emptySheet = parse('');
assert.strictEqual(emptySheet.cssRules.length, 0, 'empty CSS should produce 0 rules');

// 2. Parse basic CSS style rule and verify selectorText and declaration properties
const basicCss = 'body { color: red; margin: 10px; }';
const basicSheet = parseStylesheet(basicCss);
assert.strictEqual(basicSheet.cssRules.length, 1, 'should parse single CSSStyleRule');
const basicRule = basicSheet.cssRules[0];
assert.strictEqual(basicRule.selectorText, 'body', 'selector text must match');
assert.strictEqual(basicRule.style.color, 'red', 'style property color must match');
assert.strictEqual(basicRule.style.margin, '10px', 'style property margin must match');
assert.strictEqual(basicRule.parentStyleSheet, basicSheet, 'parentStyleSheet must point to owner stylesheet');

// 3. Parse multiple CSS rules with comments
const multiCss = '/* global styles */ h1, h2 { font-size: 20px; } .card { background: #ffffff; }';
const multiSheet = parse(multiCss);
assert.strictEqual(multiSheet.cssRules.length, 2, 'should parse two rules ignoring comments');
assert.strictEqual(multiSheet.cssRules[0].selectorText, 'h1, h2');
assert.strictEqual(multiSheet.cssRules[1].selectorText, '.card');

// 4. Parse @media rule with nested rules
const mediaCss = '@media screen and (min-width: 600px) { p { font-size: 14px; } }';
const mediaSheet = parse(mediaCss);
assert.strictEqual(mediaSheet.cssRules.length, 1, 'should parse media rule');
const mediaRule = mediaSheet.cssRules[0];
assert.strictEqual(mediaRule.media.mediaText, 'screen and (min-width: 600px)', 'media condition text must match');
assert.strictEqual(mediaRule.cssRules.length, 1, 'media rule should contain 1 nested rule');
assert.strictEqual(mediaRule.cssRules[0].selectorText, 'p', 'nested rule selector must match');
assert.strictEqual(mediaRule.cssRules[0].parentRule, mediaRule, 'nested rule parentRule must point to enclosing media rule');

// 5. Parse @keyframes rule
const keyframesCss = '@keyframes slidein { from { opacity: 0; } to { opacity: 1; } }';
const keyframesSheet = parse(keyframesCss);
assert.strictEqual(keyframesSheet.cssRules.length, 1, 'should parse keyframes rule');
const keyframesRule = keyframesSheet.cssRules[0];
assert.strictEqual(keyframesRule.name, 'slidein', 'keyframes name must match');
assert.strictEqual(keyframesRule.cssRules.length, 2, 'keyframes must contain 2 keyframe rules');
assert.strictEqual(keyframesRule.cssRules[0].keyText, 'from', 'first keyText must match');
assert.strictEqual(keyframesRule.cssRules[1].keyText, 'to', 'second keyText must match');

// 6. Parse @import rule
const importCss = '@import url("styles.css") screen;';
const importSheet = parse(importCss);
assert.strictEqual(importSheet.cssRules.length, 1, 'should parse import rule');
const importRule = importSheet.cssRules[0];
assert.strictEqual(importRule.href, 'styles.css', 'import href must match');
assert.strictEqual(importRule.media.mediaText, 'screen', 'import media query must match');

// 7. Verify extractStyleRules helper filters only style rules
const mixedCss = 'body { color: blue; } @media print { div { color: black; } } p { margin: 0; }';
const extracted = extractStyleRules(mixedCss);
assert.strictEqual(extracted.length, 2, 'should extract top-level style rules');
assert.strictEqual(extracted[0].selectorText, 'body');
assert.strictEqual(extracted[1].selectorText, 'p');

console.log('All rrweb-cssom.parse contract assertions passed.');