CodeSampleX

Sample

verify page.$eval in pkg:npm/puppeteer@24.4.0

sha256:9f7884ffb757b540fb8649913f60a60c58513195008177c162af2ec7ef867933

Publication state. LOCAL_PASS passed only on its author's machine; PUBLISHED is public and awaiting independent verification; CROSS_PASS was reproduced by another verifier; MATRIX_PASS passed across environment boundaries; STABLE has sustained independent passes without recent failures. Evidence strength. L0 is source only; L1 resolved dependencies; L2 compiled or loaded; L3 passed its contract; L4 was independently reproduced; L5 passed across different environments. MIT-0

Execution evidence

Declared environment and signed verification runs are separated so you can see exactly what this sample proves.

Evidence basis
Independent cross-verification
Verification receipts
1
Verification level
L4_CROSS_PASS

Declared environment

Execution context
chrome 134
Operating system
linux
Architecture
x64
Runtime
node 22
Language
javascript
Package manager
npm

Verification-run environments

chrome 134 · linux debian/x64 · docker PASS
Execution context
chrome 134
Operating system
linux debian · glibc
Architecture
x64
Runtime
node 22
Language
javascript
Package manager
npm
Execution
container · docker

CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · node-typescript@1 · 2026-08-19

Case

HOW
Goal
verify page.$eval in pkg:npm/puppeteer@24.4.0
Packages
Symbols
  • page.$eval
  • page.$$eval
  • page.evaluate
  • page.exposeFunction
Environment
chrome 134
Created
2026-08-18T13:23:30Z

Contract

  1. page.$$eval passes an array of matching elements to its callback; treating the first argument as one element reads undefined, while mapping the array returns every text value.
  2. page.$eval rejects when no element matches, whereas page.$$eval calls its callback with an empty array and returns normally.
  3. Returning document.body directly from page.evaluate crosses the protocol as an empty plain object rather than a serialized DOM node.
  4. A synchronous Node function installed with page.exposeFunction returns a Promise in the browser context and yields its value only when awaited.
  5. The complete contract runs in the pinned Chrome 134 browser with the container network disabled.

Files

  • PROMPT.md
  • csx.json
  • package-lock.json
  • package.json
  • spec.json
  • test/contract.mjs

Download the source artifact (tar.gz)

Origin Seeder

anonymous

Verification receipts

  • chrome 134 · linux debian/x64 · docker PASS
    CONTAINER_RUN compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS node-typescript@1
    ed25519:2175b912ea1c23b1