Fixed compilation in dev mode and added tests.

Author: archfz

.npmignore

@@ -0,0 +1 @@
+test

.travis.yml

@@ -0,0 +1,9 @@
+language: node
+
+cache:
+  directories:
+    - ./npm
+
+script:
+  - npm ci
+  - npm test

README.md

@@ -70,7 +70,7 @@ Promise.all([
 
 ## Limitations
 
-You must use the theme imports only in css modules. So for example the following is not 
+1. You must use the theme imports only in css modules. So for example the following is not 
 possible since the plugin cannot detect the theme import and do the switch.
 
 ```sass
@@ -85,3 +85,8 @@ possible since the plugin cannot detect the theme import and do the switch.
 @import './path/to/theme_one/theme.scss'
 $myOtherVar: $themeVar1 + $themeVar2
 ```
+
+2. Currently the plugin won't include plain `.css` imports from your sources or from under
+node modules into the separate themes. Since these are not themable anyway it is advised
+to separate this css imports in their own files (common chunks) and then load them for all 
+themes. This is good for caching and theme file size overall.

index.js

@@ -122,6 +122,9 @@ class MiniCssThemesWebpackPlugin {
       this.nonDefaultThemeKeys.forEach(theme => addThemeChunk(theme));
     });
 
+    let moduleDependencyHistory = [];
+    let moduleChunkHistory = [];
+
     // Required cleanup for functional final compilation.
     compiler.hooks.thisCompilation.tap(this.pluginName, (compilation) => {
       compilation.hooks.optimizeChunkModules.tap(this.pluginName, chunks => {
@@ -130,11 +133,13 @@ class MiniCssThemesWebpackPlugin {
             // Remove duplicate dependency links for the same css module as otherwise
             // webpack will concatenate IDs on the imports of these modules which will
             // produce an id to a module that doesn't in fact exist.
-            if (module.dependencies) {
+            if (module.dependencies && module.dependencies.find(dep => !dep.themed)) {
+              moduleDependencyHistory.push({module, dependencies: module.dependencies});
               module.dependencies = module.dependencies.filter(dep => !dep.themed);
             }
             // Remove from built JS duplicates of css modules classes generated by themes.
             if (module.themed) {
+              moduleChunkHistory.push({module, chunk});
               module.removeChunk(chunk);
             }
           });
@@ -143,7 +148,7 @@ class MiniCssThemesWebpackPlugin {
         // Remove theme chunks from the entry points so that they are not recognized in
         // a dependency tree and thus we can safely remove the empty JS files generated
         // by these chunks.
-        filterThemeChunks(chunks).forEach(chunk => chunk._groups.forEach(entry => entry.removeChunk(chunk)))
+        filterThemeChunks(chunks).forEach(chunk => chunk._groups.forEach(entry => entry.removeChunk(chunk)));
       });
     });
 
@@ -158,6 +163,23 @@ class MiniCssThemesWebpackPlugin {
         });
       });
     });
+
+    // When in watch mode, we need to revert previous cleanup as otherwise dependency
+    // links will be lost and the themes won't be included in future compilations.
+    compiler.hooks.watchRun.tap(this.pluginName, () => {
+      compiler.hooks.afterCompile.tap(this.pluginName, () => {
+        if (moduleDependencyHistory.length) {
+          moduleDependencyHistory.forEach((history) => history.module.dependencies = history.dependencies);
+          moduleDependencyHistory = [];
+        }
+
+        if (moduleChunkHistory.length) {
+          moduleChunkHistory.forEach((history) => history.chunk.addModule(history.module));
+          moduleChunkHistory = [];
+        }
+      });
+    });
+
   }
 }
 

test/.babelrc

@@ -0,0 +1,3 @@
+{
+  "presets": ["@babel/preset-env", "@babel/preset-react"]
+}

test/.gitignore

@@ -0,0 +1 @@
+dist