ssri 12.0.0: checkData

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 ssri.checkData in pkg:npm/ssri@12.0.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/ssri@12.0.0
Demonstrate these symbols/APIs:
  - ssri.checkData

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:sha256:42107117bb6ff91fc673f01d19a580d62bdbb62171d59352f45402f98b181419","contract":["ssri.checkData returns the matching Hash object for valid Buffer or string data against an SRI string or Integrity object","ssri.checkData returns false on digest mismatch when error option is omitted or false","ssri.checkData throws EINTEGRITY on digest mismatch and EBADSIZE on size mismatch when error: true is passed"],"goal":"verify ssri.checkData in pkg:npm/ssri@12.0.0","kind":"HOW","packages":["pkg:npm/ssri@12.0.0"],"schemaVersion":1,"symbols":["ssri.checkData"]},"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/ssri@12.0.0"],"schemaVersion":1,"subject":"pkg:npm/ssri@12.0.0","symbols":["ssri.checkData"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-ssri-checkdata",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-ssri-checkdata",
      "version": "1.0.0",
      "dependencies": {
        "ssri": "12.0.0"
      }
    },
    "node_modules/minipass": {
      "version": "7.1.3",
      "resolved": "https://registry.npmjs.org/minipass/-/minipass-7.1.3.tgz",
      "integrity": "sha512-tEBHqDnIoM/1rXME1zgka9g6Q2lcoCkxHLuc7ODJ5BxbP5d4c2Z5cGgtXAku59200Cx7diuHTOYfSBD8n6mm8A==",
      "license": "BlueOak-1.0.0",
      "engines": {
        "node": ">=16 || 14 >=14.17"
      }
    },
    "node_modules/ssri": {
      "version": "12.0.0",
      "resolved": "https://registry.npmjs.org/ssri/-/ssri-12.0.0.tgz",
      "integrity": "sha512-S7iGNosepx9RadX82oimUkvr0Ct7IjJbEbs4mJcTxst8um95J3sDYU1RBEOvdu6oL1Wek2ODI5i4MAw+dZ6cAQ==",
      "license": "ISC",
      "dependencies": {
        "minipass": "^7.0.3"
      },
      "engines": {
        "node": "^18.17.0 || >=20.5.0"
      }
    }
  }
}

{
  "name": "sample-ssri-checkdata",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "ssri": "12.0.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify ssri.checkData in pkg:npm/ssri@12.0.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/ssri@12.0.0"
  ],
  "symbols": [
    "ssri.checkData"
  ]
}

import assert from 'node:assert/strict'
import * as ssri from 'ssri'

const data = Buffer.from('subresource integrity payload')
const integrity = ssri.fromData(data, { algorithms: ['sha256', 'sha512'] })
const sriString = ssri.stringify(integrity)

// 1. Valid data returns the matching Hash object (strongest algorithm selected by default)
const matched = ssri.checkData(data, sriString)
assert.equal(matched.isHash, true)
assert.equal(matched.algorithm, 'sha512')
assert.equal(matched.digest, integrity.sha512[0].digest)

// 2. Also accepts string data and an Integrity object directly
const matchedFromStr = ssri.checkData('subresource integrity payload', integrity)
assert.equal(matchedFromStr.isHash, true)
assert.equal(matchedFromStr.algorithm, 'sha512')

// 3. Mismatched data returns false by default when error option is not set
assert.equal(ssri.checkData(Buffer.from('modified payload'), sriString), false)

// 4. With error: true, throws EINTEGRITY when digest does not match
assert.throws(
  () => ssri.checkData(Buffer.from('modified payload'), sriString, { error: true }),
  {
    code: 'EINTEGRITY',
    found: ssri.fromData(Buffer.from('modified payload'), { algorithms: ['sha512'] }),
  }
)

// 5. With error: true and size option, throws EBADSIZE when byte length does not match expected size
assert.throws(
  () => ssri.checkData(Buffer.from('short'), sriString, { error: true, size: data.length }),
  {
    code: 'EBADSIZE',
    expected: data.length,
    found: 5,
  }
)