node-hmr-plugin

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 interfece with Webpack Hot Module Replacement.

When you utilize Webpack HMR during Node 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 mode. However if your app crashes, it should be re-run after you changed source code and Webpack compilation finishes. 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 will try to restart it when application crashes 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 be treated as signal to rerun app immediately. It can be used to handle the edge case when Webpack fails to apply HMR and 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 relaunch 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.