Make it compatible with webpack 4

Author: jamesjieye

.travis.yml

@@ -2,5 +2,6 @@ language: node_js
 node_js:
   - "4"
   - "6"
+  - "8"
 script:
   - npm test

index.js

@@ -14,7 +14,11 @@ HtmlWebpackExcludeAssetsPlugin.prototype.apply = function (compiler) {
       var excludeAssets = htmlPluginData.plugin.options.excludeAssets;
       // Skip if the plugin configuration didn't set `excludeAssets`
       if (!excludeAssets) {
-        return callback(null, htmlPluginData);
+        if (callback) {
+          return callback(null, htmlPluginData);
+        } else {
+          return Promise.resolve(htmlPluginData)
+        }
       }
 
       if (excludeAssets.constructor !== Array) {
@@ -27,7 +31,11 @@ HtmlWebpackExcludeAssetsPlugin.prototype.apply = function (compiler) {
       });
 
       var result = self.processAssets(excludePatterns, htmlPluginData);
-      callback(null, result);
+      if (callback) {
+        callback(null, result);
+      } else {
+        return Promise.resolve(result)
+      }
     });
   });
 };

package.json

@@ -1,6 +1,6 @@
 {
   "name": "html-webpack-exclude-assets-plugin",
-  "version": "0.0.5",
+  "version": "0.0.6",
   "description": "Add the ability to exclude assets based on RegExp patterns",
   "main": "index.js",
   "files": [