source-map-js 1.2.1: SourceMapConsumer, SourceMapGenerator

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/source-map-js@1.2.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/source-map-js@1.2.1
Demonstrate these symbols/APIs:
  - SourceMapConsumer
  - SourceMapGenerator

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:sha256:4984ac22f8f7b7ddf6456178a7a63f1a89c101586ea82429e6afd7152eedb912","contract":["assert SourceMapGenerator builds valid v3 source map JSON with mappings and metadata","assert SourceMapConsumer resolves original position for generated position with symbol name","assert SourceMapConsumer resolves generated position for given original position","assert SourceMapConsumer retrieves embedded source content for source files","assert SourceMapConsumer iterates all mappings sequentially via eachMapping"],"goal":"verify pkg:npm/source-map-js@1.2.1","kind":"HOW","packages":["pkg:npm/source-map-js@1.2.1"],"schemaVersion":1,"symbols":["SourceMapConsumer","SourceMapGenerator"]},"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","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/source-map-js@1.2.1"],"schemaVersion":1,"subject":"pkg:npm/source-map-js@1.2.1","symbols":["SourceMapConsumer","SourceMapGenerator"],"verifierAdapter":"node-typescript@1"}

const { SourceMapConsumer, SourceMapGenerator } = require('source-map-js');

/**
 * Creates a SourceMapGenerator instance with given options.
 *
 * @param {Object} [options] - Configuration for generator (file, sourceRoot, etc.)
 * @returns {SourceMapGenerator}
 */
function createSourceMap(options) {
  return new SourceMapGenerator(options);
}

/**
 * Creates a SourceMapConsumer instance from a raw source map object or string.
 *
 * @param {Object|string} rawSourceMap - Source map object or JSON string
 * @returns {SourceMapConsumer}
 */
function consumeSourceMap(rawSourceMap) {
  return new SourceMapConsumer(rawSourceMap);
}

module.exports = {
  createSourceMap,
  consumeSourceMap,
  SourceMapConsumer,
  SourceMapGenerator,
};

{
  "name": "sample-source-map-js",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-source-map-js",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "source-map-js": "1.2.1"
      }
    },
    "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-source-map-js",
  "version": "1.0.0",
  "description": "Clean-room sample verifying pkg:npm/source-map-js@1.2.1 functionality",
  "main": "index.js",
  "license": "MIT-0",
  "dependencies": {
    "source-map-js": "1.2.1"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/source-map-js@1.2.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/source-map-js@1.2.1"
  ],
  "symbols": [
    "SourceMapConsumer",
    "SourceMapGenerator"
  ]
}

import assert from 'node:assert';
import sourceMapJs from 'source-map-js';
const { SourceMapConsumer, SourceMapGenerator } = sourceMapJs;
import { createSourceMap, consumeSourceMap } from '../index.js';

// 1. SourceMapGenerator builds valid v3 source map JSON with mappings and metadata
const generator = createSourceMap({
  file: 'min.js',
  sourceRoot: 'http://example.com/src/'
});

generator.addMapping({
  generated: { line: 1, column: 0 },
  original: { line: 1, column: 0 },
  source: 'app.js',
  name: 'calculateTotal'
});

generator.addMapping({
  generated: { line: 1, column: 15 },
  original: { line: 2, column: 4 },
  source: 'app.js'
});

const sourceCode = 'function calculateTotal() {\n  return 42;\n}';
generator.setSourceContent('app.js', sourceCode);

const mapJson = generator.toJSON();
assert.strictEqual(mapJson.version, 3, 'SourceMapGenerator produces version 3 source map');
assert.strictEqual(mapJson.file, 'min.js', 'SourceMapGenerator preserves generated file name');
assert.strictEqual(mapJson.sourceRoot, 'http://example.com/src/', 'SourceMapGenerator preserves sourceRoot');
assert.deepStrictEqual(mapJson.sources, ['app.js'], 'SourceMapGenerator registers source files');
assert.deepStrictEqual(mapJson.names, ['calculateTotal'], 'SourceMapGenerator registers identifier names');
assert.strictEqual(typeof mapJson.mappings, 'string', 'SourceMapGenerator encodes mappings string');

const mapString = generator.toString();
assert.strictEqual(typeof mapString, 'string', 'SourceMapGenerator.toString returns string');
assert.strictEqual(JSON.parse(mapString).version, 3, 'SourceMapGenerator.toString produces parseable JSON');

// 2. SourceMapConsumer resolves original position for generated position with symbol name
const consumer = consumeSourceMap(mapJson);

const origPos1 = consumer.originalPositionFor({ line: 1, column: 0 });
assert.strictEqual(origPos1.source, 'http://example.com/src/app.js', 'SourceMapConsumer resolves full source URL with sourceRoot');
assert.strictEqual(origPos1.line, 1, 'SourceMapConsumer resolves correct original line');
assert.strictEqual(origPos1.column, 0, 'SourceMapConsumer resolves correct original column');
assert.strictEqual(origPos1.name, 'calculateTotal', 'SourceMapConsumer resolves mapped symbol name');

const origPos2 = consumer.originalPositionFor({ line: 1, column: 15 });
assert.strictEqual(origPos2.source, 'http://example.com/src/app.js', 'SourceMapConsumer resolves source URL for second mapping');
assert.strictEqual(origPos2.line, 2, 'SourceMapConsumer resolves original line 2');
assert.strictEqual(origPos2.column, 4, 'SourceMapConsumer resolves original column 4');
assert.strictEqual(origPos2.name, null, 'SourceMapConsumer returns null for unnamed mapping');

// 3. SourceMapConsumer resolves generated position for given original position
const genPos = consumer.generatedPositionFor({
  source: 'http://example.com/src/app.js',
  line: 2,
  column: 4
});
assert.strictEqual(genPos.line, 1, 'SourceMapConsumer resolves generated line');
assert.strictEqual(genPos.column, 15, 'SourceMapConsumer resolves generated column');

// 4. SourceMapConsumer retrieves embedded source content for source files
assert.strictEqual(
  consumer.hasContentsOfAllSources(),
  true,
  'SourceMapConsumer indicates all sources have embedded content'
);
assert.strictEqual(
  consumer.sourceContentFor('app.js'),
  sourceCode,
  'SourceMapConsumer retrieves content by source filename'
);
assert.strictEqual(
  consumer.sourceContentFor('http://example.com/src/app.js'),
  sourceCode,
  'SourceMapConsumer retrieves content by full source URL'
);

// 5. SourceMapConsumer iterates all mappings sequentially via eachMapping
const collectedMappings = [];
consumer.eachMapping((m) => {
  collectedMappings.push({
    genLine: m.generatedLine,
    genCol: m.generatedColumn,
    origLine: m.originalLine,
    origCol: m.originalColumn,
    name: m.name
  });
});

assert.strictEqual(collectedMappings.length, 2, 'SourceMapConsumer iterates exactly 2 mappings');
assert.deepStrictEqual(
  collectedMappings[0],
  { genLine: 1, genCol: 0, origLine: 1, origCol: 0, name: 'calculateTotal' },
  'First mapping matches expected coordinates and symbol'
);
assert.deepStrictEqual(
  collectedMappings[1],
  { genLine: 1, genCol: 15, origLine: 2, origCol: 4, name: null },
  'Second mapping matches expected coordinates'
);

console.log('All contract assertions passed.');