Release v4.3.0 (#28228)

* Prep for v4.3.0

* More updates for v4.3.0.

* rerun to build docs source map

site/docs/4.3/getting-started/webpack.md

@@ -0,0 +1,93 @@
+---
+layout: docs
+title: Webpack
+description: Learn how to include Bootstrap in your project using Webpack.
+group: getting-started
+toc: true
+---
+
+## Installing Bootstrap
+
+[Install bootstrap]({{ site.baseurl }}/docs/{{ site.docs_version }}/getting-started/download/#npm) as a Node.js module using npm.
+
+## Importing JavaScript
+
+Import [Bootstrap's JavaScript]({{ site.baseurl }}/docs/{{ site.docs_version }}/getting-started/javascript/) by adding this line to your app's entry point (usually `index.js` or `app.js`):
+
+{% highlight js %}
+import 'bootstrap';
+{% endhighlight %}
+
+Alternatively, you may **import plugins individually** as needed:
+
+{% highlight js %}
+import 'bootstrap/js/dist/util';
+import 'bootstrap/js/dist/alert';
+...
+{% endhighlight %}
+
+Bootstrap is dependent on [jQuery](https://jquery.com/) and [Popper](https://popper.js.org/),
+these are defined as `peerDependencies`, this means that you will have to make sure to add both of them
+to your `package.json` using `npm install --save jquery popper.js`.
+
+## Importing Styles
+
+### Importing Precompiled Sass
+
+To enjoy the full potential of Bootstrap and customize it to your needs, use the source files as a part of your project's bundling process.
+
+First, create your own `_custom.scss` and use it to override the [built-in custom variables]({{ site.baseurl }}/docs/{{ site.docs_version }}/getting-started/theming/). Then, use your main Sass file to import your custom variables, followed by Bootstrap:
+
+{% highlight scss %}
+@import "custom";
+@import "~bootstrap/scss/bootstrap";
+{% endhighlight %}
+
+For Bootstrap to compile, make sure you install and use the required loaders: [sass-loader](https://github.com/webpack-contrib/sass-loader), [postcss-loader](https://github.com/postcss/postcss-loader) with [Autoprefixer](https://github.com/postcss/autoprefixer#webpack). With minimal setup, your webpack config should include this rule or similar:
+
+{% highlight js %}
+...
+{
+  test: /\.(scss)$/,
+  use: [{
+    loader: 'style-loader', // inject CSS to page
+  }, {
+    loader: 'css-loader', // translates CSS into CommonJS modules
+  }, {
+    loader: 'postcss-loader', // Run postcss actions
+    options: {
+      plugins: function () { // postcss plugins, can be exported to postcss.config.js
+        return [
+          require('autoprefixer')
+        ];
+      }
+    }
+  }, {
+    loader: 'sass-loader' // compiles Sass to CSS
+  }]
+},
+...
+{% endhighlight %}
+
+### Importing Compiled CSS
+
+Alternatively, you may use Bootstrap's ready-to-use CSS by simply adding this line to your project's entry point:
+
+{% highlight js %}
+import 'bootstrap/dist/css/bootstrap.min.css';
+{% endhighlight %}
+
+In this case you may use your existing rule for `css` without any special modifications to webpack config, except you don't need `sass-loader` just [style-loader](https://github.com/webpack-contrib/style-loader) and [css-loader](https://github.com/webpack-contrib/css-loader).
+
+{% highlight js %}
+...
+module: {
+  rules: [
+    {
+      test: /\.css$/,
+      use: ['style-loader', 'css-loader']
+    }
+  ]
+}
+...
+{% endhighlight %}