@jridgewell/gen-mapping 0.3.13: toEncodedMap

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 @jridgewell/gen-mapping.toEncodedMap in pkg:npm/%40jridgewell/gen-mapping@0.3.13
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40jridgewell/gen-mapping@0.3.13
Demonstrate these symbols/APIs:
  - @jridgewell/gen-mapping.toEncodedMap

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:d63b9baf94d7c8c7335b908747d1949c8c5e0b82cf5e746d1c4c56bdeb027646","constraints":{"executionContext":"node"},"contract":["toEncodedMap returns an EncodedSourceMap object with version 3 and VLQ encoded mappings","toEncodedMap serializes source mappings and symbol names correctly into VLQ encoded format","toEncodedMap includes optional file, sourceRoot, sourcesContent, and ignoreList metadata","toEncodedMap produces an empty mappings string when no mappings are added to GenMapping"],"goal":"verify @jridgewell/gen-mapping.toEncodedMap in pkg:npm/%40jridgewell/gen-mapping@0.3.13","kind":"HOW","packages":["pkg:npm/%40jridgewell/gen-mapping@0.3.13"],"schemaVersion":1,"symbols":["@jridgewell/gen-mapping.toEncodedMap"]},"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/%40jridgewell/gen-mapping@0.3.13"],"schemaVersion":1,"subject":"pkg:npm/%40jridgewell/gen-mapping@0.3.13","symbols":["@jridgewell/gen-mapping.toEncodedMap"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-gen-mapping-to-encoded-map",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-gen-mapping-to-encoded-map",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "@jridgewell/gen-mapping": "0.3.13"
      }
    },
    "node_modules/@jridgewell/gen-mapping": {
      "version": "0.3.13",
      "resolved": "https://registry.npmjs.org/@jridgewell/gen-mapping/-/gen-mapping-0.3.13.tgz",
      "integrity": "sha512-2kkt/7niJ6MgEPxF0bYdQ6etZaA+fQvDcLKckhy1yIQOzaoKjBBjSj63/aLVjYE3qhRt5dvM+uUyfCg6UKCBbA==",
      "license": "MIT",
      "dependencies": {
        "@jridgewell/sourcemap-codec": "^1.5.0",
        "@jridgewell/trace-mapping": "^0.3.24"
      }
    },
    "node_modules/@jridgewell/resolve-uri": {
      "version": "3.1.2",
      "resolved": "https://registry.npmjs.org/@jridgewell/resolve-uri/-/resolve-uri-3.1.2.tgz",
      "integrity": "sha512-bRISgCIjP20/tbWSPWMEi54QVPRZExkuD9lJL+UIxUKtwVJA8wW1Trb1jMs1RFXo1CBTNZ/5hpC9QvmKWdopKw==",
      "license": "MIT",
      "engines": {
        "node": ">=6.0.0"
      }
    },
    "node_modules/@jridgewell/sourcemap-codec": {
      "version": "1.6.0",
      "resolved": "https://registry.npmjs.org/@jridgewell/sourcemap-codec/-/sourcemap-codec-1.6.0.tgz",
      "integrity": "sha512-T7jf+5zgsZHwNJ4lvQ7/aezbyk0nNX+zJVWpmHA7VYsEx7a7qr5Rg5IbtJFqkgze5Y2sruq1RUY8Q837Od7iFw==",
      "license": "MIT"
    },
    "node_modules/@jridgewell/trace-mapping": {
      "version": "0.3.31",
      "resolved": "https://registry.npmjs.org/@jridgewell/trace-mapping/-/trace-mapping-0.3.31.tgz",
      "integrity": "sha512-zzNR+SdQSDJzc8joaeP8QQoCQr8NuYx2dIIytl1QeBEZHJ9uW6hebsrYgbz8hJwUQao3TWCMtmfV8Nu1twOLAw==",
      "license": "MIT",
      "dependencies": {
        "@jridgewell/resolve-uri": "^3.1.0",
        "@jridgewell/sourcemap-codec": "^1.4.14"
      }
    }
  }
}

{
  "name": "sample-gen-mapping-to-encoded-map",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "@jridgewell/gen-mapping": "0.3.13"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify @jridgewell/gen-mapping.toEncodedMap in pkg:npm/%40jridgewell/gen-mapping@0.3.13",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40jridgewell/gen-mapping@0.3.13"
  ],
  "symbols": [
    "@jridgewell/gen-mapping.toEncodedMap"
  ]
}

import {
  GenMapping,
  addMapping,
  addSegment,
  setSourceContent,
  setIgnore,
  toEncodedMap
} from "@jridgewell/gen-mapping";

export function createGenMapping(options = {}) {
  return new GenMapping(options);
}

export function encodeMapping(map) {
  return toEncodedMap(map);
}

export {
  GenMapping,
  addMapping,
  addSegment,
  setSourceContent,
  setIgnore,
  toEncodedMap
};

import assert from "node:assert/strict";
import {
  GenMapping,
  addMapping,
  setSourceContent,
  setIgnore,
  toEncodedMap,
  createGenMapping,
  encodeMapping
} from "../src/index.mjs";

// Test 1: toEncodedMap returns an EncodedSourceMap object with version 3 and VLQ encoded mappings
{
  const map = createGenMapping({
    file: "output.js",
    sourceRoot: "https://example.com/src"
  });
  addMapping(map, {
    generated: { line: 1, column: 0 },
    source: "input.js",
    original: { line: 1, column: 0 }
  });

  const encoded = encodeMapping(map);
  assert.equal(encoded.version, 3);
  assert.equal(encoded.file, "output.js");
  assert.equal(encoded.sourceRoot, "https://example.com/src");
  assert.equal(typeof encoded.mappings, "string");
  assert.equal(encoded.mappings, "AAAA");
  assert.deepEqual(encoded.sources, ["input.js"]);
}

// Test 2: toEncodedMap serializes source mappings and symbol names correctly into VLQ encoded format
{
  const map = new GenMapping();
  addMapping(map, {
    generated: { line: 1, column: 0 },
    source: "index.js",
    original: { line: 1, column: 0 },
    name: "init"
  });
  addMapping(map, {
    generated: { line: 2, column: 4 },
    source: "index.js",
    original: { line: 2, column: 2 },
    name: "start"
  });

  const encoded = toEncodedMap(map);
  assert.deepEqual(encoded.names, ["init", "start"]);
  assert.equal(encoded.mappings, "AAAAA;IACEC");
  assert.deepEqual(encoded.sources, ["index.js"]);
}

// Test 3: toEncodedMap includes optional file, sourceRoot, sourcesContent, and ignoreList metadata
{
  const map = new GenMapping({
    file: "minified.js",
    sourceRoot: "https://example.com/dist"
  });
  setSourceContent(map, "lib.js", "export function run() {}");
  setIgnore(map, "lib.js", true);
  addMapping(map, {
    generated: { line: 1, column: 0 },
    source: "lib.js",
    original: { line: 1, column: 0 }
  });

  const encoded = toEncodedMap(map);
  assert.equal(encoded.file, "minified.js");
  assert.equal(encoded.sourceRoot, "https://example.com/dist");
  assert.deepEqual(encoded.sourcesContent, ["export function run() {}"]);
  assert.deepEqual(encoded.ignoreList, [0]);
}

// Test 4: toEncodedMap produces an empty mappings string when no mappings are added to GenMapping
{
  const map = new GenMapping();
  const encoded = toEncodedMap(map);

  assert.equal(encoded.version, 3);
  assert.equal(encoded.mappings, "");
  assert.deepEqual(encoded.names, []);
  assert.deepEqual(encoded.sources, []);
  assert.deepEqual(encoded.sourcesContent, []);
}

console.log("All @jridgewell/gen-mapping.toEncodedMap contract tests passed successfully.");