update for dart 2.0 and fix some bugs

.gitignore

@@ -36,3 +36,8 @@ node_modules
 *.tgz
 
 example/bundle.js
+
+# idea
+.DS_Store
+node_modules
+.idea

README.md

@@ -26,6 +26,22 @@ module.exports = {
 }
 ```
 
+```js
+// webpack-chain
+module.exports = {
+  chainWebpack: config => {
+    config.module.rule('dart')
+      .test(/\.dart$/)
+      .use('dart-loader')
+      .loader('dart-loader')
+      .options({
+        minimize: '-m'
+      })
+      .end()
+  }
+}
+```
+
 Make sure you have the `dart2js` binary somewhere in your `PATH`.
 
 ### Example

index.js

@@ -1,19 +1,67 @@
 const child_process = require('child_process');
 const fs = require('fs');
 const path = require('path');
+const colors = require('colors');
+const loaderUtils = require('loader-utils');
 
-module.exports = function(source) {
-  const callback = this.async();
-  const tmp = path.join(__dirname, 'tmp');
-  const fname = path.basename(this.resourcePath, '.dart');
-  const cmd = `dart2js -o '${path.join(tmp, `${fname}.js`)}' '${this.resourcePath}'`;
-  child_process.execSync(`rm -rf '${tmp}'`);
-  child_process.execSync(`mkdir -p '${tmp}'`);
-
-  child_process.exec(cmd, function(error, stdout, stderr) {
-    if (error) { return callback(error, null); }
-    const out = fs.readFileSync(path.join(tmp, `${fname}.js`), 'utf8');
-    callback(null, out);
-  });
+/**
+ * @summary
+ * The map between the options passed to the loader
+ * and the command-line `dart2js` utility flags.
+ * Option '--enable-checked-mode' is not needed in Dart 2.0
+ */
+const optsMap = {
+    'minimize': '-m'
 };
 
+/**
+ * @summary
+ * Construct a command-line `dart2js` utility options string
+ * from a given loader options object.
+ *
+ * @return {string}
+ */
+const constructDart2JsOptions = (options) => {
+    if (options instanceof Object) {
+        const optsStr = Object.keys(options).reduce((res, key) => {
+            const hasKey = Object.keys(optsMap).indexOf(key) !== -1;
+            const mapping = optsMap[key];
+            return hasKey ? `${res} ${mapping}` : res;
+        }, '');
+        return optsStr;
+    } else {
+        return '';
+    }
+}
+
+
+module.exports = function(source) {
+    // Retrieve the options that were passed to the loader
+    const options = loaderUtils.getOptions(this);
+
+    // Construct the command-line options to the `dart2js` utility
+    const dart2JsOptionsStr = constructDart2JsOptions(options);
+
+    const callback = this.async();
+    const tmp = path.join(__dirname, 'tmp');
+    const fname = path.basename(this.resourcePath, '.dart');
+    const cmd = `dart2js ${dart2JsOptionsStr} -o '${path.join(tmp, `${fname}.js`)}' '${this.resourcePath}'`;
+    child_process.execSync(`rm -rf '${tmp}'`);
+    child_process.execSync(`mkdir -p '${tmp}'`);
+
+    child_process.exec(cmd, (error, stdout, stderr) => {
+        // If there was an error
+        if (error) {
+            // Output it into the console
+            const msg = stdout.red;
+            console.log('\n');
+            console.error(' ERROR '.black.bgRed, 'Failed to compile dart to js with errors');
+            console.log(msg);
+
+            // Return from the function and call the callback
+            return callback(error, null);
+        }
+        const out = fs.readFileSync(path.join(tmp, `${fname}.js`), 'utf8');
+        callback(null, out);
+    });
+};

package.json

@@ -4,6 +4,8 @@
   "author": "Matt Dziuban",
   "description": "Dart loader module for webpack",
   "dependencies": {
+    "colors": "^1.4.0",
+    "loader-utils": "^1.2.3"
   },
   "repository": {
     "type": "git",