@jridgewell/trace-mapping 0.3.31: sourceContentFor

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/trace-mapping.sourceContentFor in pkg:npm/%40jridgewell/trace-mapping@0.3.31
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40jridgewell/trace-mapping@0.3.31
Demonstrate these symbols/APIs:
  - @jridgewell/trace-mapping.sourceContentFor

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:sha256:5237a04d316955944c34148c3fef8e3da3f402c81153920709e659199306ffd6","contract":["sourceContentFor returns the embedded source content for a source file present in sourcesContent","sourceContentFor returns null for a source file without content or when sourcesContent is not provided","sourceContentFor returns null for an unknown or unmapped source file path","sourceContentFor resolves sources correctly when sourceRoot is configured in the source map"],"goal":"verify @jridgewell/trace-mapping.sourceContentFor in pkg:npm/%40jridgewell/trace-mapping@0.3.31","kind":"HOW","packages":["pkg:npm/%40jridgewell/trace-mapping@0.3.31"],"schemaVersion":1,"symbols":["@jridgewell/trace-mapping.sourceContentFor"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","language":"javascript","libc":"glibc","libcVersion":"2.39","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/trace-mapping@0.3.31"],"schemaVersion":1,"subject":"pkg:npm/%40jridgewell/trace-mapping@0.3.31","symbols":["@jridgewell/trace-mapping.sourceContentFor"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-trace-mapping-source-content-for",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-trace-mapping-source-content-for",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "@jridgewell/trace-mapping": "0.3.31"
      }
    },
    "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": "1.5.5",
      "resolved": "https://registry.npmjs.org/@jridgewell/sourcemap-codec/-/sourcemap-codec-1.5.5.tgz",
      "integrity": "sha512-cYQ9310grqxueWbl+WuIUIaiUaDcj7WOq5fVhEljNVgRfOUhY9fy2zTvfoqWsnebh8Sl70VScFbICvJnLKB0Og==",
      "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-trace-mapping-source-content-for",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "@jridgewell/trace-mapping": "0.3.31"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify @jridgewell/trace-mapping.sourceContentFor in pkg:npm/%40jridgewell/trace-mapping@0.3.31",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40jridgewell/trace-mapping@0.3.31"
  ],
  "symbols": [
    "@jridgewell/trace-mapping.sourceContentFor"
  ]
}

import { TraceMap, sourceContentFor } from "@jridgewell/trace-mapping";

export function createTraceMap(map) {
  return new TraceMap(map);
}

export function getSourceContent(tracer, source) {
  return sourceContentFor(tracer, source);
}

import assert from "node:assert/strict";
import { TraceMap, sourceContentFor } from "@jridgewell/trace-mapping";
import { createTraceMap, getSourceContent } from "../src/index.mjs";

// Test 1: sourceContentFor returns the embedded source content for a source file present in sourcesContent
{
  const map = {
    version: 3,
    sources: ["input.js", "utils.js"],
    sourcesContent: ["export const x = 42;", "export function add(a, b) { return a + b; }"],
    mappings: "AAAA;"
  };
  const tracer = createTraceMap(map);
  assert.equal(getSourceContent(tracer, "input.js"), "export const x = 42;");
  assert.equal(getSourceContent(tracer, "utils.js"), "export function add(a, b) { return a + b; }");
  assert.equal(sourceContentFor(tracer, "input.js"), "export const x = 42;");
}

// Test 2: sourceContentFor returns null for a source file without content or when sourcesContent is not provided
{
  const mapWithNull = {
    version: 3,
    sources: ["has-content.js", "no-content.js"],
    sourcesContent: ["const a = 1;", null],
    mappings: "AAAA;"
  };
  const tracer1 = createTraceMap(mapWithNull);
  assert.equal(getSourceContent(tracer1, "has-content.js"), "const a = 1;");
  assert.equal(getSourceContent(tracer1, "no-content.js"), null);

  const mapWithoutSourcesContent = {
    version: 3,
    sources: ["input.js"],
    mappings: "AAAA;"
  };
  const tracer2 = createTraceMap(mapWithoutSourcesContent);
  assert.equal(getSourceContent(tracer2, "input.js"), null);
}

// Test 3: sourceContentFor returns null for an unknown or unmapped source file path
{
  const map = {
    version: 3,
    sources: ["file1.js"],
    sourcesContent: ["const ok = true;"],
    mappings: "AAAA;"
  };
  const tracer = createTraceMap(map);
  assert.equal(getSourceContent(tracer, "unknown.js"), null);
  assert.equal(getSourceContent(tracer, ""), null);
  assert.equal(getSourceContent(tracer, null), null);
  assert.equal(getSourceContent(tracer, undefined), null);
}

// Test 4: sourceContentFor resolves sources correctly when sourceRoot is configured in the source map
{
  const mapWithRoot = {
    version: 3,
    sourceRoot: "https://example.com/src/",
    sources: ["app.js"],
    sourcesContent: ["console.log('root app');"],
    mappings: "AAAA;"
  };
  const tracer = createTraceMap(mapWithRoot);
  assert.equal(getSourceContent(tracer, "https://example.com/src/app.js"), "console.log('root app');");
  assert.equal(getSourceContent(tracer, "app.js"), "console.log('root app');");
}

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