Node HMR Webpack Plugin

node-hmr-plugin is a Webpack plugin that allows running your Node app during development in such a way that it doesn't interfere with Webpack Hot Module Replacement.

When you utilize Webpack HMR during Node server app development, the Webpack normally reloads app code itself. You shouldn't watch for source code changes with external tool like nodemon, because Webpack will picks up changes itself and in more efficient way. However, if your app crashes, it should be re-started after you changed source code and Webpack compilation finished. The plugin is exactly about supporting this workflow.

Installation

Use Yarn or NPM to install Node HMR Webpack Plugin as a development dependency:

# with Yarn
yarn add -D node-hmr-plugin

# with NPM
npm install -D node-hmr-plugin

Configuration

The plugin will do nothing in non-watch mode. In watch mode, the plugin will launch node application and try to restart it when application crashed and new code changes were made.

webpack.config.js

const NodeHmrPlugin = require('node-hmr-plugin');

module.exports = [
  target: 'node',
  ...
  plugins: [
    new HotModuleReplacementPlugin(),
    new NodeHmrPlugin()
  ]
};

Plugin options

cmd (string) (default='{app}')

Command template string default: '{app}', it can be for example: '--inspect {app} some_arg'. The {app} is replaced with actual path to the compiled bundle.

restartOnExitCodes (number[]) (default=none)

Exit code list that should result in app restart, immediately. It can be used to handle the edge case when Webpack fails to apply HMR. For example, you can have the code like this inside your app:

module.hot.status(event => {
  if (event === 'abort' || event === 'fail') {
    process.exit(250);
  }
});

and pass restartOnExitCodes: [250] option to the plugin to force immediate application re-start on HMR failure.

logLevel (string) (default='info')

Log level, one of trace, debug, info, warn, error, silent. If you want to silence plugin, pass logLevel: 'info' option.

License

Copyright © 2019 SysGears (Cyprus) Limited. This source code is licensed under the MIT license.