devkit: writeConfig w/ optional callback

external/amber-dev/lib/config.js

@@ -7,19 +7,18 @@ var configBuilder = require('amd-config-builder'),
     path = require('path'),
     fs = require('fs');
 
-exports.writeConfig = function (searchDir, fileForConfig) {
+exports.writeConfig = function (searchDir, fileForConfig, callback) {
     searchDir = searchDir || path.join(__dirname, '../../..');
     fileForConfig = fileForConfig || 'config.js';
+    callback = callback || function (err) { if (err) throw err; };
 
     configBuilder.produceConfigObject(searchDir, function (err, result) {
-        if (err) throw err;
+        if (err) return callback(err);
         var text = "/* DO NOT EDIT! This file is generated. */\n" +
             "\n" +
             "var require;\n" +
             "if (!require) require = {config: function (x) {require = x;}};\n" +
             "require.config(" + JSON.stringify(result, null, 2) + ");";
-        fs.writeFile(path.join(searchDir, fileForConfig), text, function (err) {
+        fs.writeFile(path.join(searchDir, fileForConfig), text, callback);
-            if (err) throw err;
-        });
     });
 };