Piping2

0.4.1 verified Fri May 01 auth: no javascript maintenance

Piping2 is a hot-reload utility for Node.js that automatically restarts your application when files change, without requiring a wrapper binary. Version 0.4.1 is the latest stable release. Unlike nodemon or node-supervisor, it uses the cluster API to spawn your app in a worker process, enabling clean restarts without external daemons. It supports transpiler integration (e.g., Babel), file watching via chokidar, and optional require hook for selective monitoring. This package is considered unstable and intended for development only. Note that piping2 is a fork of the original piping package, with no active maintenance.

Common errors

error TypeError: piping is not a function ↓

cause Importing piping2 using ESM `import piping from 'piping2'` fails because the module exports a CommonJS function.

fix

Use const piping = require('piping2')

error Your application code runs twice. Please check your piping setup. ↓

cause Not guarding application logic with the `if (piping()) { ... }` pattern, so code executes in both master and worker processes.

fix

Wrap your app code with if (!require('piping2')()) { return; }

error Error: ENOENT: no such file or directory, watch ... ↓

cause File watching fails because the specified 'main' path does not exist or is incorrect.

fix

Ensure the 'main' option points to an existing file, e.g., ./server.js

Warnings

breaking Unstable cluster API used; crashes may occur on some Node versions. ↓

fix Consider switching to nodemon or supervisor for production stability.

gotcha Your file is invoked twice: first by the master process (returns false), then by the worker (returns true). ↓

fix Always wrap application logic in an `if (piping()) { ... }` block or guard with `return`.

gotcha If 'hook' is false (default), all files in the main file's directory are watched. Use 'ignore' to exclude node_modules. ↓

fix Set `hook: true` to only watch required files, but note that files required before piping() are not tracked.

breaking Depends on chokidar, which may have breaking changes between major versions. ↓

fix Pin chokidar version in your project's package.json if issues arise.

Install

npm install piping2

yarn add piping2

pnpm add piping2

Imports

default (function)
wrong
```
import piping from 'piping2'
```
correct
```
const piping = require('piping2')
```
piping2 is a CommonJS module, no ESM exports. Use require().
piping() with options object
wrong
```
const { piping } = require('piping2')
```
correct
```
require('piping2')({ main: './server.js', hook: true })
```
The module exports a single function; destructuring does not work.
piping() with string argument
wrong
```
require('piping2').default('./server.js')
```
correct
```
require('piping2')('./server.js')
```
Passing a string sets the 'main' option.

Quickstart

Basic usage: require piping2, pass configuration, and only run app logic when piping returns true (worker process).

const piping = require('piping2');
if (!piping({ main: './app.js', hook: false })) { return; }
console.log('App hot-reloading with piping2!');