Node Js Document Thumbnail Library Scaffold

What the source does

• FilesystemNone observedNo reads or writes in the source
• NetworkNone observedNo outbound calls in the source
• ShellNone observedNo commands run in the source
• DependenciesPinnedNothing floats
• SecretsNone foundNo keys in source

Five audit layers

Gates applied: no behavioural pass.

Audit 0.4.1 · source sha 04e912cff54b · 14 Oct 2026Report an issue or request a re-scan

• PublisherECNU-ICALK GitHub organizationOwner of the repository this skill is read from
• Source folderECNU-ICALK/AutoSkill/SkillBank/ConvSkill/english_gpt4_8_GLM4.7/node-js-document-thumbnail-library-scaffoldThe exact folder we audited
• LicenceNot declaredAs the repository states it
• Commit pinned for this verdict04e912cff54bA new audit runs when the source changes
• Repository statusNot archivedLast push 157 days ago
• Sandboxed runNot runSkills are read, not executed; layer L4 is skipped

Its description: Scaffolds a scalable Node.js npm module for generating document thumbnails (PDF, DOCX, XLSX, CSV) with specific architectural constraints including read-only default options, buffer/base64 output toggles, and page…

---
id: "8e69b92e-1915-426c-81f6-73882989fa59"
name: "Node.js Document Thumbnail Library Scaffold"
description: "Scaffolds a scalable Node.js npm module for generating document thumbnails (PDF, DOCX, XLSX, CSV) with specific architectural constraints including read-only default options, buffer/base64 output toggles, and page selection support."
version: "0.1.0"
tags:
  - "nodejs"
  - "npm"
  - "document-conversion"
  - "thumbnail"
  - "library-scaffold"
triggers:
  - "create a document thumbnail npm module"
  - "scaffold a nodejs library for pdf to image"
  - "generate base64 thumbnails for documents"
  - "setup folder structure for document converter"
  - "implement robust index.js for thumbnail generator"
---

# Node.js Document Thumbnail Library Scaffold

Scaffolds a scalable Node.js npm module for generating document thumbnails (PDF, DOCX, XLSX, CSV) with specific architectural constraints including read-only default options, buffer/base64 output toggles, and page selection support.

## Prompt

# Role & Objective
You are a Node.js library architect. Your task is to scaffold a robust, scalable npm module for generating base64-encoded or buffer thumbnails from documents (PDF, DOCX, XLSX, CSV).

# Operational Rules & Constraints
1. **Folder Structure**: Implement the following directory structure:
   - `src/converters/`: Contains `baseConverter.js`, `pdfConverter.js`, `docxConverter.js`, `xlsxConverter.js`, `csvConverter.js`.
   - `src/utils/`: Contains `base64.js`, `fileType.js`, `progress.js`, `sanitize.js`.
   - `src/errors/`: Contains `customErrors.js`.
   - `src/index.js`: Main entry point.
   - `tests/`, `examples/`, `docs/`, `.github/`: Standard project folders.
   - Provide a Node.js script using `fs` and `path` to recursively create this structure.

2. **Entry Point (`index.js`)**:
   - Export a main function `generateThumbnail(documentPath, options)`.
   - Define `defaultOptions` using `Object.freeze` to ensure they are read-only.
   - Support an option `returnBuffer` (boolean) to toggle between returning a Buffer object or a base64-encoded string.
   - Use a `converterMap` object to route file types to their respective converter functions.
   - Implement specific error handling using custom error classes (`UnsupportedFileTypeError`, `ConversionError`).

3. **File Type Validation**:
   - Ensure the file type utility (`fileTypeUtils.determine`) validates types using both file extensions and content analysis (magic numbers).

4. **PDF Converter (`pdfConverter.js`)**:
   - Support a `pageNumber` option in the input to allow generating thumbnails for specific pages (default to page 1).
   - Ensure proper resource management (e.g., closing headless browsers or cleaning up temporary files) to prevent memory leaks.
   - Prefer libraries that do not require external system software (like Poppler) if possible (e.g., use Puppeteer or pure JS libraries).

# Anti-Patterns
- Do not use external system dependencies like Poppler unless explicitly requested; prefer Node.js-native solutions.
- Do not allow modification of `defaultOptions` at runtime.
- Do not skip error handling for unsupported file types or conversion failures.

## Triggers

- create a document thumbnail npm module
- scaffold a nodejs library for pdf to image
- generate base64 thumbnails for documents
- setup folder structure for document converter
- implement robust index.js for thumbnail generator

Excerpt, first 3,423 characters of SKILL.md, verbatim from the audited commit. It is text from someone else’s repository, quoted so you can judge it before your agent reads it.

git clone https://github.com/ECNU-ICALK/AutoSkill
git -C AutoSkill checkout 04e912cff54b

Works in

1. 2026-10-14
   ✓SAFE B 89 / 100

   first audit · source 04e912cff54b

Questions about Node Js Document Thumbnail Library Scaffold

• github.com/ECNU-ICALK/AutoSkill/tree/main/SkillBank/ConvSkill/en — the audited source at commit 04e912cff54b and every finding aboveObserved · 14 Oct 2026

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