A lightweight, cross-runtime file watcher with glob pattern support for Node.js, Deno, and Bun. Zero heavyweight dependencies — just native file watching APIs for maximum performance. 🚀

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Install

npm install @push.rocks/smartchok
# or
pnpm add @push.rocks/smartchok

Features

🌐 Cross-Runtime — Works seamlessly on Node.js 20+, Deno, and Bun 🔍 Glob Pattern Support — Watch files using familiar patterns like **/*.ts and src/**/*.{js,jsx} 📡 RxJS Observables — Subscribe to file system events using reactive streams 🔄 Dynamic Watching — Add or remove watch patterns at runtime ⚡ Native Performance — Uses fs.watch() on Node.js/Bun and Deno.watchFs() on Deno ✨ Write Stabilization — Built-in debouncing prevents duplicate events during file writes 🎯 TypeScript First — Full TypeScript support with comprehensive type definitions 📦 Minimal Footprint — No chokidar, no FSEvents bindings — just ~500 lines of focused code

Usage

Basic Setup

import { Smartwatch } from '@push.rocks/smartchok';

// Create a watcher with glob patterns
const watcher = new Smartwatch([
  './src/**/*.ts',           // Watch all TypeScript files in src
  './public/assets/**/*'     // Watch all files in public/assets
]);

// Start watching
await watcher.start();

Subscribing to File Events

Use RxJS observables to react to file system changes:

// Get an observable for file changes
const changeObservable = await watcher.getObservableFor('change');

changeObservable.subscribe({
  next: ([path, stats]) => {
    console.log(`File changed: ${path}`);
    console.log(`New size: ${stats?.size} bytes`);
  },
  error: (err) => {
    console.error(`Error: ${err}`);
  }
});

// Watch for new files
const addObservable = await watcher.getObservableFor('add');
addObservable.subscribe(([path]) => {
  console.log(`File added: ${path}`);
});

// Watch for deleted files
const unlinkObservable = await watcher.getObservableFor('unlink');
unlinkObservable.subscribe(([path]) => {
  console.log(`File deleted: ${path}`);
});

Supported Events

Event	Description
`add`	File has been added
`addDir`	Directory has been added
`change`	File has been modified
`unlink`	File has been removed
`unlinkDir`	Directory has been removed
`error`	Error occurred
`ready`	Initial scan complete

Dynamic Watch Management

Add or remove patterns while the watcher is running:

const watcher = new Smartwatch(['./src/**/*.ts']);
await watcher.start();

// Add more patterns to watch
watcher.add(['./tests/**/*.spec.ts', './config/*.json']);

// Remove a pattern
watcher.remove('./src/**/*.test.ts');

Stopping the Watcher

// Stop watching when done
await watcher.stop();

Complete Example

import { Smartwatch } from '@push.rocks/smartchok';

async function watchProject() {
  // Initialize with patterns
  const watcher = new Smartwatch([
    './src/**/*.ts',
    './package.json'
  ]);

  // Start the watcher
  await watcher.start();
  console.log('👀 Watching for changes...');

  // Subscribe to changes
  const changes = await watcher.getObservableFor('change');
  changes.subscribe(([path, stats]) => {
    console.log(`📝 Modified: ${path}`);
    console.log(`   Size: ${stats?.size ?? 'unknown'} bytes`);
  });

  // Subscribe to new files
  const additions = await watcher.getObservableFor('add');
  additions.subscribe(([path]) => {
    console.log(`✨ New file: ${path}`);
  });

  // Subscribe to deletions
  const deletions = await watcher.getObservableFor('unlink');
  deletions.subscribe(([path]) => {
    console.log(`🗑️ Deleted: ${path}`);
  });

  // Handle graceful shutdown
  process.on('SIGINT', async () => {
    console.log('\n🛑 Stopping watcher...');
    await watcher.stop();
    process.exit(0);
  });
}

watchProject();

How It Works

smartchok uses native file watching APIs for each runtime:

Runtime	API Used
Node.js 20+	`fs.watch({ recursive: true })`
Deno	`Deno.watchFs()`
Bun	Node.js compatibility layer

Under the Hood

Native file watching APIs don't support glob patterns directly, so smartchok handles pattern matching internally:

Base path extraction — Extracts the static portion from each glob pattern (e.g., ./src/ from ./src/**/*.ts)
Efficient watching — Native watchers monitor only the base directories
Pattern filtering — Events are filtered through picomatch matchers before emission
Event deduplication — Built-in throttling prevents duplicate events from rapid file operations

Write Stabilization

smartchok includes built-in write stabilization (similar to chokidar's awaitWriteFinish). When a file is being written, events are held until the file size stabilizes, preventing multiple events for a single write operation.

Default settings:

Stability threshold: 300ms
Poll interval: 100ms

Requirements

Runtime	Version
Node.js	20+ (required for native recursive watching)
Deno	Any version with `Deno.watchFs()` support
Bun	Uses Node.js compatibility

API Reference

`Smartwatch`

Constructor

new Smartwatch(patterns: string[])

Creates a new Smartwatch instance with the given glob patterns.

Parameters:

patterns — Array of glob patterns to watch (e.g., ['./src/**/*.ts', './config/*.json'])

Methods

Method	Returns	Description
`start()`	`Promise<void>`	Starts watching for file changes
`stop()`	`Promise<void>`	Stops the file watcher and cleans up resources
`add(patterns: string[])`	`void`	Adds additional patterns to watch
`remove(pattern: string)`	`void`	Removes a pattern from the watch list
`getObservableFor(event: TFsEvent)`	`Promise<Observable<[string, Stats]>>`	Returns an RxJS observable for the specified event

Properties

Property	Type	Description
`status`	`'idle' \| 'starting' \| 'watching'`	Current watcher status

Types

type TFsEvent = 'add' | 'addDir' | 'change' | 'error' | 'unlink' | 'unlinkDir' | 'ready' | 'raw';
type TSmartwatchStatus = 'idle' | 'starting' | 'watching';

Why smartchok?

Feature	smartchok	chokidar
Native API	✅ Direct `fs.watch`	❌ FSEvents bindings
Cross-runtime	✅ Node, Deno, Bun	❌ Node only
Dependencies	4 small packages	~20 packages
Write stabilization	✅ Built-in	✅ Built-in
Glob support	✅ picomatch	✅ anymatch
Bundle size	~15KB	~200KB+

If you need a lightweight file watcher without native compilation headaches, smartchok has you covered.

License and Legal Information

This repository contains open-source code licensed under the MIT License. A copy of the license can be found in the LICENSE file.

Please note: The MIT License does not grant permission to use the trade names, trademarks, service marks, or product names of the project, except as required for reasonable and customary use in describing the origin of the work and reproducing the content of the NOTICE file.

Trademarks

This project is owned and maintained by Task Venture Capital GmbH. The names and logos associated with Task Venture Capital GmbH and any related products or services are trademarks of Task Venture Capital GmbH or third parties, and are not included within the scope of the MIT license granted herein.

Use of these trademarks must comply with Task Venture Capital GmbH's Trademark Guidelines or the guidelines of the respective third-party owners, and any usage must be approved in writing. Third-party trademarks used herein are the property of their respective owners and used only in a descriptive manner, e.g. for an implementation of an API or similar.

readme.md

@push.rocks/smartchok