add a command for static syntax check with babel.js

README.md

@@ -7,4 +7,11 @@ Using docker
  
 Using bash
 
-```zip -r build/p4t.xpi chrome``` 
+```zip -r build/p4t.xpi chrome```
+
+## Check syntax statically
+
+You can parse the code with [Babel](https://babeljs.io/) in order to
+catch syntax errors. After installing with `npm install` just run:
+
+    npm run syntaxCheck

package.json

@@ -4,6 +4,7 @@
   "dependencies": {},
   "devDependencies": {
     "atob": "^2.1.2",
+    "babel-cli": "^6.26.0",
     "btoa": "^1.2.1",
     "chai": "*",
     "chai-as-promised": "*",
@@ -13,6 +14,7 @@
     "xhr2": "^0.1.4"
   },
   "scripts": {
-    "test": "./node_modules/.bin/mocha tests/unit/*.js tests/features/*.js"
+      "test": "./node_modules/.bin/mocha tests/unit/*.js tests/features/*.js",
+      "syntaxCheck": "./node_modules/.bin/babel chrome -d /tmp/babelOutput"
   }
 }