feat: override publicPath setting. (#230)

* Allow user to override publicPath setting.

This allows users to use Webpack's `auto` option for publicPath and still set a public path for the dev server.

* updating docs and tests

* cleanup logic to allow empty string as publicPath

Author: nicksrandall

README.md

@@ -230,6 +230,12 @@ If [truthy](https://developer.mozilla.org/en-US/docs/Glossary/Truthy), the modul
 
 If a value of `'minimal'` is set, the progress indicator will render as a small, colored bar at the top of the window. This can be useful when the default fancy progress indicator interferes with elements in the page.
 
+### `publicPath`
+Type: `String`<br>
+Default: `webpack.output.publicPath`
+
+Sets the publicPath that the server should use to serve assets. You probably only need to set this explicitly if you are using [Webpack's `auto` feature](https://webpack.js.org/guides/public-path/#automatic-publicpath) for public path detection.
+
 ### `ramdisk`
 Type: `boolean | Object`<br>
 Default: `false`<br>

lib/index.js

@@ -38,6 +38,7 @@ const defaults = {
   open: false,
   port: 55555,
   progress: true,
+  publicPath: null,
   ramdisk: false,
   secure: false,
   static: null,
@@ -186,7 +187,10 @@ class WebpackPluginServe extends EventEmitter {
     }
 
     // check static paths for publicPath. #100
-    const { publicPath } = compiler.options.output;
+    const publicPath =
+      this.options.publicPath === null
+        ? compiler.options.output.publicPath
+        : this.options.publicPath;
     if (publicPath) {
       let foundPath = false;
       for (const path of this.options.static) {
@@ -200,7 +204,7 @@ class WebpackPluginServe extends EventEmitter {
       /* istanbul ignore next */
       if (!foundPath) {
         this.log.warn(
-          chalk`{bold {yellow Warning}} The value of {yellow \`output.publicPath\`} was not found on the filesystem in any static paths specified\n`
+          chalk`{bold {yellow Warning}} The value of {yellow \`publicPath\`} was not found on the filesystem in any static paths specified\n`
         );
       }
     }

lib/validate.js

@@ -52,6 +52,7 @@ module.exports = {
       open: union([boolean(), type({})]),
       port: union([max(integer(), 65535), promise]),
       progress: union([boolean(), literal('minimal')]),
+      publicPath: nullable(string()),
       ramdisk: union([boolean(), type({})]),
       secure: never(),
       static: nullable(