If you're using Webpack 2+ then you shouldn't need this plugin anymore. Under normal circumstances Webpack should already exit with a proper exit code. As such, this plugin does not officially support Webpack 2+.

If you don't get the correct exit code with Webpack 2+ then this is most likely a bug in a plugin you're using, or you're running into a Webpack bug. In either case I strongly recommend to isolate the problem and file issues at the appropriate repositories. In the mean time you could try to use this plugin as a temporary workaround.

Webpack plugin that will make the process return status code 1 when it finishes with errors in single-run mode.

npm install webpack-fail-plugin --save-dev

var failPlugin = require('webpack-fail-plugin');

module.exports = {
	//config
	plugins: [
		failPlugin
	]
}

Credits to @happypoulp.