ssri 12.0.0: fromData

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.fromData 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.fromData

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:sha256:000068c2ac73efd52ab23ae83da4ae29d9a7d0a40dfdae4fa3a73d1f461a3ec9","contract":["ssri.fromData generates sha512 Integrity metadata by default from Buffer or string inputs","ssri.fromData supports multiple algorithms and attaches options to each generated Hash entry","Integrity metadata produced by ssri.fromData validates the original payload via ssri.checkData"],"goal":"verify ssri.fromData in pkg:npm/ssri@12.0.0","kind":"HOW","packages":["pkg:npm/ssri@12.0.0"],"schemaVersion":1,"symbols":["ssri.fromData"]},"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.fromData"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-ssri-fromdata",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-ssri-fromdata",
      "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-fromdata",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "ssri": "12.0.0"
  }
}

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

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

const dataBuffer = Buffer.from('subresource integrity payload')

// 1. Default algorithm (sha512) from Buffer and string
const defaultIntegrity = ssri.fromData(dataBuffer)
assert.equal(defaultIntegrity.isIntegrity, true)
assert.equal(defaultIntegrity.isEmpty(), false)
assert.equal(defaultIntegrity.pickAlgorithm(), 'sha512')
assert.equal(Array.isArray(defaultIntegrity.sha512), true)
assert.equal(defaultIntegrity.sha512.length, 1)
assert.equal(defaultIntegrity.sha512[0].algorithm, 'sha512')

const fromString = ssri.fromData('subresource integrity payload')
assert.equal(fromString.toString(), defaultIntegrity.toString())

// 2. Multiple algorithms and per-hash options
const multiAlgo = ssri.fromData(dataBuffer, {
  algorithms: ['sha256', 'sha384', 'sha512'],
  options: ['optA', 'optB'],
})
assert.equal(multiAlgo.isIntegrity, true)
assert.equal(multiAlgo.sha256.length, 1)
assert.equal(multiAlgo.sha384.length, 1)
assert.equal(multiAlgo.sha512.length, 1)
assert.deepEqual(multiAlgo.sha256[0].options, ['optA', 'optB'])
assert.match(
  multiAlgo.toString(),
  /^sha256-[A-Za-z0-9+/=]+\?optA\?optB sha384-[A-Za-z0-9+/=]+\?optA\?optB sha512-[A-Za-z0-9+/=]+\?optA\?optB$/
)

// 3. Verify generated Integrity matches the input data via checkData
const matched = ssri.checkData(dataBuffer, multiAlgo)
assert.equal(matched.algorithm, 'sha512')
assert.equal(matched.digest, defaultIntegrity.sha512[0].digest)