It sucks to Ctrl-C your build script & server just to install a dependency you didn't know you needed until now.

Instead, use require or import how you normally would and npm install will happen automatically to install & save missing dependencies while you work!

$ npm install --save-dev npm-install-webpack-plugin

In your webpack.config.js:

plugins: [
  new NpmInstallPlugin();
],

This is equivalent to:

plugins: [
  new NpmInstallPlugin({
    // Use --save or --save-dev
    dev: false,
    // Install missing peerDependencies
    peerDependencies: true,
    // Reduce amount of console logging
    quiet: false,
    // npm command used inside company, yarn is not supported yet
    npm: 'tnpm'
  });
],

You can provide a Function to the dev to make it dynamic:

plugins: [
  new NpmInstallPlugin({
    dev: function(module, path) {
      return [
        "babel-preset-react-hmre",
        "webpack-dev-middleware",
        "webpack-hot-middleware",
      ].indexOf(module) !== -1;
    },
  }),
],

• [x] Works with both Webpack ^v1.12.0 and ^2.1.0-beta.0.
• [x] Auto-installs .babelrc plugins & presets.
• [x] Supports both ES5 & ES6 Modules. (e.g. require, import)
• [x] Supports Namespaced packages. (e.g. @cycle/dom)
• [x] Supports Dot-delimited packages. (e.g. lodash.capitalize)
• [x] Supports CSS imports. (e.g. @import "~bootstrap")
• [x] Supports Webpack loaders. (e.g. babel-loader, file-loader, etc.)
• [x] Supports inline Webpack loaders. (e.g. require("bundle?lazy!./App")
• [x] Auto-installs missing peerDependencies. (e.g. @cycle/core will automatically install rx@*)
• [x] Supports Webpack's resolve.alias & resolve.root configuration. (e.g. require("react") can alias to react-lite)