CodeSampleX

Sample

Intercept and customize subresource loading in JSDOM using ResourceLoader

sha256:729cd83d1c1f9d920bc16f81b26620669e5f6eb3dd0f9c878ce052f183c7f713

This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured. How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people. MIT-0

Execution evidence

The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.

Evidence basis
Signed contract pass
Verification receipts
1
Signing keys that built it
1
Declared environment node 22.23 linux 24 · ubuntu · glibc 2.39 x64 node 22.23 javascript npm 10

Verification-run environments

Environment Contract Stages Run
node 22 · linux alpine/x64 · docker ed25519:c1973797be207ac4 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · node-typescript@1node:22-alpine@sha256:c610fcdfb1d5…
2026-08-28

Case

HOW
Goal
Intercept and customize subresource loading in JSDOM using ResourceLoader
Packages
Symbols
  • JSDOM
  • ResourceLoader
Environment
node 22.23.2
Created
2026-08-28T06:56:19Z

Contract

  1. ResourceLoader constructor accepts configuration options including userAgent, proxy, and strictSSL.
  2. Instantiating JSDOM without configuring resources suppresses all external subresource fetching for scripts and stylesheets.
  3. Attaching a custom ResourceLoader subclass intercepts subresource fetch requests and passes the requesting element reference in fetch options.
  4. Returning a Buffer promise from ResourceLoader fetch resolves synthetic external script content and executes it within the JSDOM window context under runScripts dangerously.
  5. Returning a Buffer promise from ResourceLoader fetch parses external stylesheets into document.styleSheets rules.
  6. Returning null from ResourceLoader fetch silently blocks subresource fetching without throwing exceptions, emitting jsdomError, or firing element event handlers.
  7. Rejecting the promise returned from ResourceLoader fetch triggers element onerror handlers and emits a jsdomError event to VirtualConsole.

Files

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

Download the source artifact (tar.gz)

Origin Seeder

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