document the purpose of the fork

Author: bagnier

README.md

@@ -1,11 +1,77 @@
-# HackMD API Clients
+# Add ETag Support to HackMD API Client
 
-This repository contains a set of packages for interacting with the [HackMD API](https://hackmd.io/).
+This repository contains a set of packages for interacting with the [HackMD API](https://hackmd.io/), forked from [upstream repository](https://github.com/hackmdio/api-client).
 
-## Node.JS
+## Summary
+This repo implements ETag support for HackMD API client operations, enabling conditional requests and response caching.
 
-See [README](./nodejs)
+## Technical Details
+  - Added ETag support to GET, POST, and PATCH operations for user notes
+  - ETags are now accessible in responses for `getNote`, `createNote`, `updateNote`, and `updateNoteContent`
+  - Implemented proper handling of 304 Not Modified responses for conditional GET requests
 
-## LICENSE
+## Code Examples
 
-MIT
+### 1. Creating a note
+```typescript
+// Create a note and receive ETag in response
+const newNote = await client.createNote({
+title: 'New Note',
+content: 'Initial content'
+})
+console.log(newNote.etag) // 'W/"abc123"'
+```
+
+### 2. Reading a note
+```typescript
+// Get the note and store its ETag
+const note = await client.getNote(newNote.id)
+console.log(note.etag) // 'W/"abc123"'
+```
+
+### 3. Updating a note
+```typescript
+// Update the note and receive a new ETag
+const updatedNote = await client.updateNoteContent(note.id, 'Updated content')
+console.log(updatedNote.etag) // 'W/"xyz789"' (different from original)
+```
+
+### 4. Conditional read with original ETag (will get new content)
+```typescript
+// Try reading with the original ETag
+const result1 = await client.getNote(note.id, {
+etag: note.etag // original ETag that's now outdated
+})
+
+// Content has changed, so we get the new version
+console.log(result1.status) // undefined (normal 200 response)
+console.log(result1.content) // 'Updated content'
+console.log(result1.etag) // 'W/"xyz789"'
+```
+
+### 5. Conditional read with updated ETag (will get 304)
+```typescript
+// Try reading with the latest ETag
+const result2 = await client.getNote(note.id, {
+etag: updatedNote.etag // current ETag
+})
+
+// Content hasn't changed, so we get 304 Not Modified
+console.log(result2.status) // 304
+console.log(result2.content) // undefined
+console.log(result2.etag) // 'W/"xyz789"' (same as before)
+```
+
+## Limitations
+  - The HackMD API server does not currently support If-Match headers in PATCH requests, limiting conditional updates
+  - Current implementation focuses on user notes operations - the most commonly used  endpoints.
+
+## Implementation Approach
+  - Made ETag usage optional to preserve backward compatibility
+  - Included ETags automatically in responses when available
+  - Required explicit opt-in for conditional requests via the options parameter
+  - Focused implementation on user notes operations only (not team notes)
+  - Comprehensive test suite verifies all ETag functionality scenarios
+
+## Security
+  - Updated dependencies to fix vulnerabilities