fix: uglifyJs merge with object and array mode

Author: hubcarl

lib/core/config.js

@@ -103,6 +103,10 @@ class Config {
     return this.utils.normalizePublicPath(publicPath);
   }
 
+  get devtool() {
+    return this.webpackConfig.devtool;
+  }
+
   get host() {
     let host = '';
     const config = this.config;

lib/core/optimize.js

@@ -65,26 +65,30 @@ module.exports = class WebpackOptimize {
       delete this.optimization.minimizer;
     }
     // compatible old config
-    const { plugins = {} } = this.ctx.config;
-    if (this.ctx.prod && !this.optimization.minimizer && this.ctx.utils.isObject(plugins.uglifyJs)) {
-      const args = plugins.uglifyJs.args || plugins.uglifyJs;
-      const options = this.ctx.merge({
-        cache: true,
-        parallel: 2,
-        sourceMap: false,
-        uglifyOptions: {
-          warnings: false,
-          compress: {
-            dead_code: true,
-            drop_console: true,
-            drop_debugger: true
-          },
-          output: {
-            comments: false
+    if (this.ctx.prod && !this.optimization.minimizer) {
+      const uglifyJs = this.ctx.getConfigPlugin('uglifyJs');
+      if (uglifyJs) {
+        const args = this.ctx.utils.isObject(uglifyJs) ? uglifyJs.args || uglifyJs : {};
+        const options = this.ctx.merge({
+          cache: true,
+          parallel: 4,
+          sourceMap: !!this.ctx.devtool,
+          uglifyOptions: {
+            ie8: false,
+            warnings: false,
+            compress: {
+              dead_code: true,
+              drop_console: true,
+              drop_debugger: true
+            },
+            output: {
+              comments: false
+            }
           }
-        }
-      }, args);
-      this.optimization.minimizer = [ new UglifyJsPlugin(options) ];
+        }, args);
+        this.optimization.minimize = false;
+        this.optimization.minimizer = [ new UglifyJsPlugin(options) ];
+      }
     }
     return this.optimization;
   }

lib/core/plugin.js

@@ -6,9 +6,10 @@ module.exports = {
   getConfigPlugin(label) {
     const plugins = this.config.plugins || {};
     if (Array.isArray(plugins)) {
-      return plugins.find(plugin => {
-        return plugin[label] || {};
+      const plugin = plugins.find(item => {
+        return item.hasOwnProperty(label);
       });
+      return plugin && plugin[label] || {};
     }
     return plugins[label] || {};
   },