Added ability to use additional optimizers

README.md

@@ -78,7 +78,15 @@ rules: [{
         webp: {
           quality: 75
         }
-      }
+      },
+      additionalPlugins: [
+        {
+          plugin: 'imagemin-jpegtran',
+          options: {
+            progressive: true
+          }
+        }
+      ]
     },
   ],
 }]
@@ -96,6 +104,10 @@ And optional optimizers:
 
 - [webp](https://github.com/imagemin/imagemin-webp) — *Compress JPG & PNG images into WEBP*
 
+And you may include additional imagemin plugins and their options by defining them in additionalPlugins. You must manually install each additional plugin as a node module before using it with image-webpack-loader.
+
+[Plugins](https://www.npmjs.com/search?q=keywords:imageminplugin) to use.
+
 _Default optimizers can be disabled by specifying `optimizer.enabled: false`, and optional ones can be enabled by simply putting them in the options_
 
 If you are using Webpack 1, take a look at the [old docs](http://webpack.github.io/docs/using-loaders.html) (or consider upgrading).

index.js

@@ -37,8 +37,10 @@ module.exports = function(content) {
     optipng: config.optipng || {},
     svgo: config.svgo || {},
     // optional optimizers
-    webp: config.webp || null
+    webp: config.webp || null,
+    additionalPlugins: config.additionalPlugins || []
   };
+
   // Remove in interlaced, progressive and optimizationLevel checks in new major version
   if (config.hasOwnProperty('interlaced')) {
     options.gifsicle.interlaced = config.interlaced;
@@ -75,6 +77,11 @@ module.exports = function(content) {
     // optional optimizers
     if(options.webp)
       plugins.push(require('imagemin-webp')(options.webp));
+    // additional optimizers
+    options.additionalPlugins.forEach((plugin) => {
+      plugin.options = plugin.options || {};
+      plugins.push(require(plugin.plugin)(plugin.options));
+    });
 
     imagemin
       .buffer(content, {

package.json

@@ -13,23 +13,26 @@
     "test:webpack2": "npm install -q webpack@2.x && npm run test:clean && webpack --config test/webpack2.config.js",
     "test:webpack3": "npm install -q webpack@3.x && npm run test:clean && webpack --config test/webpack2.config.js",
     "test:webpack4": "npm install -q webpack@4.x webpack-cli && npm run test:clean && webpack --config test/webpack4.config.js",
+    "test:webpack-additional": "npm install -q webpack@4.x webpack-cli@3.3.10 imagemin-jpegtran && npm run test:clean && webpack --config test/webpack-additional.config.js",
     "test:clean": "rimraf test/public/assets",
     "test": "npm run test:webpack1 && npm run test:webpack2 && npm run test:webpack3 && npm run test:webpack4"
   },
   "dependencies": {
     "imagemin": "^5.3.1",
     "imagemin-gifsicle": "^5.2.0",
+    "imagemin-jpegtran": "^6.0.0",
     "imagemin-mozjpeg": "^7.0.0",
     "imagemin-optipng": "^5.2.1",
     "imagemin-pngquant": "^5.1.0",
     "imagemin-svgo": "^6.0.0",
     "imagemin-webp": "^4.1.0",
     "loader-utils": "^1.1.0",
-    "object-assign": "^4.1.1"
+    "object-assign": "^4.1.1",
+    "webpack": "^4.41.2"
   },
   "devDependencies": {
     "file-loader": "^1.1.11",
     "rimraf": "^2.6.2",
-    "webpack-cli": "^2.1.3"
+    "webpack-cli": "^3.3.10"
   }
 }

test/webpack-additional.config.js

@@ -0,0 +1,88 @@
+'use strict';
+var path = require('path');
+var webpack = require('webpack');
+
+var assetsPath = path.join(__dirname, 'public/assets');
+
+var loaderOptions = {
+  mozjpeg: {
+    quality: 65
+  },
+  pngquant: {
+    quality: '65-90',
+    speed: 4
+  },
+  svgo: {
+    plugins: [
+      {
+        removeViewBox: false
+      },
+      {
+        removeEmptyAttrs: false
+      }
+    ]
+  },
+  additionalPlugins: [
+    {
+      plugin: 'imagemin-jpegtran',
+      options: {
+        progressive: true
+      }
+    }
+  ],
+  gifsicle: {
+    optimizationLevel: 7,
+    interlaced: false
+  },
+  optipng: {
+    optimizationLevel: 7,
+    interlaced: false
+  },
+  webp: {
+    quality: 75
+  }
+};
+
+var fileLoaderOptions = {
+  hash: 'sha512',
+  digest: 'hex',
+  name: '[hash].[ext]'
+};
+
+module.exports = [
+  {
+    mode: 'production',
+    entry: './test/app.js',
+    output: {
+      path: assetsPath,
+      filename: 'app.[hash].js'
+    },
+    module: {
+      rules: [
+        {
+          test: /.*\.(gif|png|jpe?g|svg|webp)$/i,
+          use: [
+            {
+              loader: 'file-loader',
+              options: fileLoaderOptions
+            },
+            {
+              loader: require.resolve('../'),
+              options: loaderOptions
+            }
+          ]
+        },
+        {
+          test: /\.bmp$/i,
+          use: [
+            {
+              loader: 'file-loader',
+              options: fileLoaderOptions
+            },
+            require.resolve('../') // loaderUtils.getOptions() returns null for this one
+          ]
+        }
+      ]
+    }
+  }
+];