feat: added documentation for the postTransformPublicPath option

Author: fabb

README.md

@@ -245,6 +245,32 @@ module.exports = {
 };
 ```
 
+### `postTransformPublicPath`
+
+Type: `Function`
+Default: `undefined`
+
+Specifies a custom function to post-process the generated public path. This can be used to prepend or append dynamic global variables that are only available at runtime, like `__webpack_public_path__`. This would not be possible with just `publicPath`, since it stringifies the values.
+
+**webpack.config.js**
+
+```js
+module.exports = {
+  module: {
+    rules: [
+      {
+        test: /\.(png|jpg|gif)$/,
+        loader: 'file-loader',
+        options: {
+          publicPath: '/some/path/',
+          postTransformPublicPath: (p) => `__webpack_public_path__ + ${p}`,
+        },
+      },
+    ],
+  },
+};
+```
+
 ### `context`
 
 Type: `String`

src/options.json

@@ -55,6 +55,7 @@
     "name": "should be {String} or {Function} (https://github.com/webpack-contrib/file-loader#name)",
     "outputPath": "should be {String} or {Function} (https://github.com/webpack-contrib/file-loader#outputpath)",
     "publicPath": "should be {String} or {Function} (https://github.com/webpack-contrib/file-loader#publicpath)",
+    "postTransformPublicPath": "should be {Function} (https://github.com/webpack-contrib/file-loader#posttransformpublicpath)",
     "context": "should be {String} (https://github.com/webpack-contrib/file-loader#context)",
     "emitFile": "should be {Boolean} (https://github.com/webpack-contrib/file-loader#emitfile)",
     "regExp": "should be {String} or {RegExp} (https://github.com/webpack-contrib/file-loader#regexp)"