data-uri-to-buffer 6.0.2: dataUriToBuffer

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/data-uri-to-buffer@6.0.2
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/data-uri-to-buffer@6.0.2

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:b6af8cd3ed1b2f44ff1ce165e5ca27056b62b136a48712ed7e6e26f8fe97505a","contract":["dataUriToBuffer decodes plain text data URI with default MIME type and charset","dataUriToBuffer decodes base64 encoded text data URI with explicit MIME type","dataUriToBuffer decodes base64 encoded JSON data URI with custom charset","dataUriToBuffer accepts URL instances in addition to string URIs","dataUriToBuffer decodes binary data URI with application/octet-stream MIME type","dataUriToBuffer handles empty data URI returning empty buffer","dataUriToBuffer parses custom MIME type parameters into typeFull and charset","dataUriToBuffer throws TypeError when passed a non-data URI protocol","dataUriToBuffer throws TypeError when passed a malformed data URI without comma"],"goal":"verify pkg:npm/data-uri-to-buffer@6.0.2","kind":"HOW","packages":["pkg:npm/data-uri-to-buffer@6.0.2"],"schemaVersion":1,"symbols":["dataUriToBuffer"]},"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/data-uri-to-buffer@6.0.2"],"schemaVersion":1,"subject":"pkg:npm/data-uri-to-buffer@6.0.2","symbols":["dataUriToBuffer"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-data-uri-to-buffer",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-data-uri-to-buffer",
      "version": "1.0.0",
      "dependencies": {
        "data-uri-to-buffer": "6.0.2"
      }
    },
    "node_modules/data-uri-to-buffer": {
      "version": "6.0.2",
      "resolved": "https://registry.npmjs.org/data-uri-to-buffer/-/data-uri-to-buffer-6.0.2.tgz",
      "integrity": "sha512-7hvf7/GW8e86rW0ptuwS3OcBGDjIi6SZva7hCyWC0yYry2cOPmLIjXAUHI6DK2HsnwJd9ifmt57i8eV2n4YNpw==",
      "license": "MIT",
      "engines": {
        "node": ">= 14"
      }
    }
  }
}

{
  "name": "sample-data-uri-to-buffer",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "dependencies": {
    "data-uri-to-buffer": "6.0.2"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/data-uri-to-buffer@6.0.2",
  "kind": "HOW",
  "packages": [
    "pkg:npm/data-uri-to-buffer@6.0.2"
  ]
}

import assert from 'node:assert/strict';
import { dataUriToBuffer } from 'data-uri-to-buffer';

// 1. dataUriToBuffer decodes plain text data URI with default MIME type and charset
{
  const res = dataUriToBuffer('data:,Hello%2C%20World!');
  assert.equal(res.type, 'text/plain');
  assert.equal(res.typeFull, 'text/plain;charset=US-ASCII');
  assert.equal(res.charset, 'US-ASCII');
  assert.equal(new TextDecoder().decode(res.buffer), 'Hello, World!');
}

// 2. dataUriToBuffer decodes base64 encoded text data URI with explicit MIME type
{
  const res = dataUriToBuffer('data:text/plain;base64,SGVsbG8sIFdvcmxkIQ==');
  assert.equal(res.type, 'text/plain');
  assert.equal(res.typeFull, 'text/plain');
  assert.equal(res.charset, '');
  assert.equal(new TextDecoder().decode(res.buffer), 'Hello, World!');
}

// 3. dataUriToBuffer decodes base64 encoded JSON data URI with custom charset
{
  const res = dataUriToBuffer('data:application/json;charset=utf-8;base64,eyJmb28iOiJiYXIifQ==');
  assert.equal(res.type, 'application/json');
  assert.equal(res.typeFull, 'application/json;charset=utf-8');
  assert.equal(res.charset, 'utf-8');
  assert.equal(new TextDecoder().decode(res.buffer), '{"foo":"bar"}');
}

// 4. dataUriToBuffer accepts URL instances in addition to string URIs
{
  const res = dataUriToBuffer(new URL('data:text/plain;base64,VGVzdA=='));
  assert.equal(new TextDecoder().decode(res.buffer), 'Test');
}

// 5. dataUriToBuffer decodes binary data URI with application/octet-stream MIME type
{
  const res = dataUriToBuffer('data:application/octet-stream;base64,AQIDBA==');
  assert.equal(res.type, 'application/octet-stream');
  assert.deepEqual(Array.from(new Uint8Array(res.buffer)), [1, 2, 3, 4]);
}

// 6. dataUriToBuffer handles empty data URI returning empty buffer
{
  const res = dataUriToBuffer('data:,');
  assert.equal(res.type, 'text/plain');
  assert.equal(res.typeFull, 'text/plain;charset=US-ASCII');
  assert.equal(res.charset, 'US-ASCII');
  assert.equal(res.buffer.byteLength, 0);
}

// 7. dataUriToBuffer parses custom MIME type parameters into typeFull and charset
{
  const res = dataUriToBuffer('data:text/plain;charset=UTF-8;foo=bar,test');
  assert.equal(res.type, 'text/plain');
  assert.equal(res.typeFull, 'text/plain;charset=UTF-8;foo=bar');
  assert.equal(res.charset, 'UTF-8');
  assert.equal(new TextDecoder().decode(res.buffer), 'test');
}

// 8. dataUriToBuffer throws TypeError when passed a non-data URI protocol
assert.throws(
  () => dataUriToBuffer('https://example.com'),
  {
    name: 'TypeError',
    message: '`uri` does not appear to be a Data URI (must begin with "data:")'
  }
);

// 9. dataUriToBuffer throws TypeError when passed a malformed data URI without comma
assert.throws(
  () => dataUriToBuffer('data:text/plain'),
  {
    name: 'TypeError',
    message: 'malformed data: URI'
  }
);