md-codeblock-patcher

LLM Code Block Applier: A zero-dependency utility that extracts fenced code blocks from markdown responses and applies them directly to the workspace as full overwrites or git-like SEARCH/REPLACE diff patches.

⚡ Features

• Zero Runtime Dependencies: Ultra lightweight and fast.
• FilePath Annotation Extraction: Automatically resolves targets from inline code comments (e.g., // filepath: path/to/file or <!-- filepath: ... -->).
• SEARCH/REPLACE Patch Parsing: Applies standard search/replace diff chunks dynamically onto local files without corrupting code.
• Whole File Overwrites: Safely creates or overwrites target files with clean code outputs.

📦 Installation

npm install md-codeblock-patcher

🚀 Usage

1. CLI Usage

Extract and apply patches from a markdown log file:

npx md-codeblock-patcher response.md

# Set base workspace directory
npx md-codeblock-patcher response.md --dir ./packages/app

2. Programmatic API

import { extractCodeBlocks, applyBlockPatch } from 'md-codeblock-patcher';

const llmResponse = `
Here is the fix for your utility file:

\`\`\`typescript
<<<<<<< SEARCH
export function add(a, b) {
  return a + b;
}
=======
export function add(a: number, b: number): number {
  return a + b;
}
>>>>>>> REPLACE
\`\`\`
`;

const blocks = extractCodeBlocks(llmResponse);
// Manually assign filepath if not present in markdown comments
blocks[0].filePath = "src/math.ts";

const success = await applyBlockPatch(blocks[0], process.cwd());
if (success) {
  console.log("Successfully patched src/math.ts");
}

📄 License

MIT License.