added error to minification step

src/meta/js.js

@@ -133,11 +133,16 @@ module.exports = function(Meta) {
 				mapStream = minifier.stdio[2],
 				mapString = '',
 				step = 0,
-				onComplete = function() {
+				onComplete = function(err) {
 					if (step === 0) {
 						return step++;
 					}
 
+					if (err) {
+						winston.error('[meta/js] Minification failed: ' + err.message);
+						process.exit(0);
+					}
+
 					Meta.js.cache = minifiedString;
 					Meta.js.map = mapString;
 					winston.info('[meta/js] Compilation complete');