diff -u b/core/.eslintrc.json b/core/.eslintrc.json
--- b/core/.eslintrc.json
+++ b/core/.eslintrc.json
@@ -35,5 +35,6 @@
       "requireReturn": false
     }],
-    "brace-style": ["error", "stroustrup"]
+    "brace-style": ["error", "stroustrup"],
+    "no-unused-vars": [1]
   }
 }
diff -u b/core/npm-shrinkwrap.json b/core/npm-shrinkwrap.json
--- b/core/npm-shrinkwrap.json
+++ b/core/npm-shrinkwrap.json
@@ -22,9 +22,9 @@
       }
     },
     "ajv": {
-      "version": "4.11.2",
+      "version": "4.11.5",
       "from": "ajv@>=4.7.0 <5.0.0",
-      "resolved": "https://registry.npmjs.org/ajv/-/ajv-4.11.2.tgz",
+      "resolved": "https://registry.npmjs.org/ajv/-/ajv-4.11.5.tgz",
       "dev": true
     },
     "ajv-keywords": {
@@ -130,15 +130,21 @@
       "dev": true
     },
     "babel-core": {
-      "version": "6.22.1",
-      "from": "babel-core@6.22.1",
-      "resolved": "https://registry.npmjs.org/babel-core/-/babel-core-6.22.1.tgz",
+      "version": "6.24.0",
+      "from": "babel-core@6.24.0",
+      "resolved": "https://registry.npmjs.org/babel-core/-/babel-core-6.24.0.tgz",
       "dev": true
     },
     "babel-generator": {
+      "version": "6.24.0",
+      "from": "babel-generator@>=6.24.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-generator/-/babel-generator-6.24.0.tgz",
+      "dev": true
+    },
+    "babel-helper-builder-binary-assignment-operator-visitor": {
       "version": "6.22.0",
-      "from": "babel-generator@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-generator/-/babel-generator-6.22.0.tgz",
+      "from": "babel-helper-builder-binary-assignment-operator-visitor@>=6.22.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-helper-builder-binary-assignment-operator-visitor/-/babel-helper-builder-binary-assignment-operator-visitor-6.22.0.tgz",
       "dev": true
     },
     "babel-helper-call-delegate": {
@@ -148,15 +154,21 @@
       "dev": true
     },
     "babel-helper-define-map": {
+      "version": "6.23.0",
+      "from": "babel-helper-define-map@>=6.23.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-helper-define-map/-/babel-helper-define-map-6.23.0.tgz",
+      "dev": true
+    },
+    "babel-helper-explode-assignable-expression": {
       "version": "6.22.0",
-      "from": "babel-helper-define-map@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-helper-define-map/-/babel-helper-define-map-6.22.0.tgz",
+      "from": "babel-helper-explode-assignable-expression@>=6.22.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-helper-explode-assignable-expression/-/babel-helper-explode-assignable-expression-6.22.0.tgz",
       "dev": true
     },
     "babel-helper-function-name": {
-      "version": "6.22.0",
+      "version": "6.23.0",
       "from": "babel-helper-function-name@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-helper-function-name/-/babel-helper-function-name-6.22.0.tgz",
+      "resolved": "https://registry.npmjs.org/babel-helper-function-name/-/babel-helper-function-name-6.23.0.tgz",
       "dev": true
     },
     "babel-helper-get-function-arity": {
@@ -172,9 +184,9 @@
       "dev": true
     },
     "babel-helper-optimise-call-expression": {
-      "version": "6.22.0",
-      "from": "babel-helper-optimise-call-expression@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-helper-optimise-call-expression/-/babel-helper-optimise-call-expression-6.22.0.tgz",
+      "version": "6.23.0",
+      "from": "babel-helper-optimise-call-expression@>=6.23.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-helper-optimise-call-expression/-/babel-helper-optimise-call-expression-6.23.0.tgz",
       "dev": true
     },
     "babel-helper-regex": {
@@ -183,22 +195,28 @@
       "resolved": "https://registry.npmjs.org/babel-helper-regex/-/babel-helper-regex-6.22.0.tgz",
       "dev": true
     },
-    "babel-helper-replace-supers": {
+    "babel-helper-remap-async-to-generator": {
       "version": "6.22.0",
-      "from": "babel-helper-replace-supers@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-helper-replace-supers/-/babel-helper-replace-supers-6.22.0.tgz",
+      "from": "babel-helper-remap-async-to-generator@>=6.22.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-helper-remap-async-to-generator/-/babel-helper-remap-async-to-generator-6.22.0.tgz",
+      "dev": true
+    },
+    "babel-helper-replace-supers": {
+      "version": "6.23.0",
+      "from": "babel-helper-replace-supers@>=6.23.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-helper-replace-supers/-/babel-helper-replace-supers-6.23.0.tgz",
       "dev": true
     },
     "babel-helpers": {
-      "version": "6.22.0",
-      "from": "babel-helpers@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-helpers/-/babel-helpers-6.22.0.tgz",
+      "version": "6.23.0",
+      "from": "babel-helpers@>=6.23.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-helpers/-/babel-helpers-6.23.0.tgz",
       "dev": true
     },
     "babel-messages": {
-      "version": "6.22.0",
-      "from": "babel-messages@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-messages/-/babel-messages-6.22.0.tgz",
+      "version": "6.23.0",
+      "from": "babel-messages@>=6.23.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-messages/-/babel-messages-6.23.0.tgz",
       "dev": true
     },
     "babel-plugin-check-es2015-constants": {
@@ -207,6 +225,30 @@
       "resolved": "https://registry.npmjs.org/babel-plugin-check-es2015-constants/-/babel-plugin-check-es2015-constants-6.22.0.tgz",
       "dev": true
     },
+    "babel-plugin-syntax-async-functions": {
+      "version": "6.13.0",
+      "from": "babel-plugin-syntax-async-functions@>=6.8.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-syntax-async-functions/-/babel-plugin-syntax-async-functions-6.13.0.tgz",
+      "dev": true
+    },
+    "babel-plugin-syntax-exponentiation-operator": {
+      "version": "6.13.0",
+      "from": "babel-plugin-syntax-exponentiation-operator@>=6.8.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-syntax-exponentiation-operator/-/babel-plugin-syntax-exponentiation-operator-6.13.0.tgz",
+      "dev": true
+    },
+    "babel-plugin-syntax-trailing-function-commas": {
+      "version": "6.22.0",
+      "from": "babel-plugin-syntax-trailing-function-commas@>=6.22.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-syntax-trailing-function-commas/-/babel-plugin-syntax-trailing-function-commas-6.22.0.tgz",
+      "dev": true
+    },
+    "babel-plugin-transform-async-to-generator": {
+      "version": "6.22.0",
+      "from": "babel-plugin-transform-async-to-generator@>=6.22.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-async-to-generator/-/babel-plugin-transform-async-to-generator-6.22.0.tgz",
+      "dev": true
+    },
     "babel-plugin-transform-es2015-arrow-functions": {
       "version": "6.22.0",
       "from": "babel-plugin-transform-es2015-arrow-functions@>=6.22.0 <7.0.0",
@@ -220,15 +262,15 @@
       "dev": true
     },
     "babel-plugin-transform-es2015-block-scoping": {
-      "version": "6.22.0",
-      "from": "babel-plugin-transform-es2015-block-scoping@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-block-scoping/-/babel-plugin-transform-es2015-block-scoping-6.22.0.tgz",
+      "version": "6.23.0",
+      "from": "babel-plugin-transform-es2015-block-scoping@>=6.23.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-block-scoping/-/babel-plugin-transform-es2015-block-scoping-6.23.0.tgz",
       "dev": true
     },
     "babel-plugin-transform-es2015-classes": {
-      "version": "6.22.0",
-      "from": "babel-plugin-transform-es2015-classes@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-classes/-/babel-plugin-transform-es2015-classes-6.22.0.tgz",
+      "version": "6.23.0",
+      "from": "babel-plugin-transform-es2015-classes@>=6.23.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-classes/-/babel-plugin-transform-es2015-classes-6.23.0.tgz",
       "dev": true
     },
     "babel-plugin-transform-es2015-computed-properties": {
@@ -238,9 +280,9 @@
       "dev": true
     },
     "babel-plugin-transform-es2015-destructuring": {
-      "version": "6.22.0",
-      "from": "babel-plugin-transform-es2015-destructuring@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-destructuring/-/babel-plugin-transform-es2015-destructuring-6.22.0.tgz",
+      "version": "6.23.0",
+      "from": "babel-plugin-transform-es2015-destructuring@>=6.23.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-destructuring/-/babel-plugin-transform-es2015-destructuring-6.23.0.tgz",
       "dev": true
     },
     "babel-plugin-transform-es2015-duplicate-keys": {
@@ -250,9 +292,9 @@
       "dev": true
     },
     "babel-plugin-transform-es2015-for-of": {
-      "version": "6.22.0",
-      "from": "babel-plugin-transform-es2015-for-of@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-for-of/-/babel-plugin-transform-es2015-for-of-6.22.0.tgz",
+      "version": "6.23.0",
+      "from": "babel-plugin-transform-es2015-for-of@>=6.23.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-for-of/-/babel-plugin-transform-es2015-for-of-6.23.0.tgz",
       "dev": true
     },
     "babel-plugin-transform-es2015-function-name": {
@@ -268,27 +310,27 @@
       "dev": true
     },
     "babel-plugin-transform-es2015-modules-amd": {
-      "version": "6.22.0",
+      "version": "6.24.0",
       "from": "babel-plugin-transform-es2015-modules-amd@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-modules-amd/-/babel-plugin-transform-es2015-modules-amd-6.22.0.tgz",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-modules-amd/-/babel-plugin-transform-es2015-modules-amd-6.24.0.tgz",
       "dev": true
     },
     "babel-plugin-transform-es2015-modules-commonjs": {
-      "version": "6.22.0",
-      "from": "babel-plugin-transform-es2015-modules-commonjs@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-modules-commonjs/-/babel-plugin-transform-es2015-modules-commonjs-6.22.0.tgz",
+      "version": "6.24.0",
+      "from": "babel-plugin-transform-es2015-modules-commonjs@>=6.23.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-modules-commonjs/-/babel-plugin-transform-es2015-modules-commonjs-6.24.0.tgz",
       "dev": true
     },
     "babel-plugin-transform-es2015-modules-systemjs": {
-      "version": "6.22.0",
-      "from": "babel-plugin-transform-es2015-modules-systemjs@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-modules-systemjs/-/babel-plugin-transform-es2015-modules-systemjs-6.22.0.tgz",
+      "version": "6.23.0",
+      "from": "babel-plugin-transform-es2015-modules-systemjs@>=6.23.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-modules-systemjs/-/babel-plugin-transform-es2015-modules-systemjs-6.23.0.tgz",
       "dev": true
     },
     "babel-plugin-transform-es2015-modules-umd": {
-      "version": "6.22.0",
-      "from": "babel-plugin-transform-es2015-modules-umd@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-modules-umd/-/babel-plugin-transform-es2015-modules-umd-6.22.0.tgz",
+      "version": "6.24.0",
+      "from": "babel-plugin-transform-es2015-modules-umd@>=6.23.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-modules-umd/-/babel-plugin-transform-es2015-modules-umd-6.24.0.tgz",
       "dev": true
     },
     "babel-plugin-transform-es2015-object-super": {
@@ -298,9 +340,9 @@
       "dev": true
     },
     "babel-plugin-transform-es2015-parameters": {
-      "version": "6.22.0",
-      "from": "babel-plugin-transform-es2015-parameters@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-parameters/-/babel-plugin-transform-es2015-parameters-6.22.0.tgz",
+      "version": "6.23.0",
+      "from": "babel-plugin-transform-es2015-parameters@>=6.23.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-parameters/-/babel-plugin-transform-es2015-parameters-6.23.0.tgz",
       "dev": true
     },
     "babel-plugin-transform-es2015-shorthand-properties": {
@@ -328,9 +370,9 @@
       "dev": true
     },
     "babel-plugin-transform-es2015-typeof-symbol": {
-      "version": "6.22.0",
-      "from": "babel-plugin-transform-es2015-typeof-symbol@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-typeof-symbol/-/babel-plugin-transform-es2015-typeof-symbol-6.22.0.tgz",
+      "version": "6.23.0",
+      "from": "babel-plugin-transform-es2015-typeof-symbol@>=6.23.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-typeof-symbol/-/babel-plugin-transform-es2015-typeof-symbol-6.23.0.tgz",
       "dev": true
     },
     "babel-plugin-transform-es2015-unicode-regex": {
@@ -339,6 +381,12 @@
       "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-unicode-regex/-/babel-plugin-transform-es2015-unicode-regex-6.22.0.tgz",
       "dev": true
     },
+    "babel-plugin-transform-exponentiation-operator": {
+      "version": "6.22.0",
+      "from": "babel-plugin-transform-exponentiation-operator@>=6.22.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-exponentiation-operator/-/babel-plugin-transform-exponentiation-operator-6.22.0.tgz",
+      "dev": true
+    },
     "babel-plugin-transform-regenerator": {
       "version": "6.22.0",
       "from": "babel-plugin-transform-regenerator@>=6.22.0 <7.0.0",
@@ -351,46 +399,46 @@
       "resolved": "https://registry.npmjs.org/babel-plugin-transform-strict-mode/-/babel-plugin-transform-strict-mode-6.22.0.tgz",
       "dev": true
     },
-    "babel-preset-es2015": {
-      "version": "6.22.0",
-      "from": "babel-preset-es2015@6.22.0",
-      "resolved": "https://registry.npmjs.org/babel-preset-es2015/-/babel-preset-es2015-6.22.0.tgz",
+    "babel-preset-env": {
+      "version": "1.2.2",
+      "from": "babel-preset-env@1.2.2",
+      "resolved": "https://registry.npmjs.org/babel-preset-env/-/babel-preset-env-1.2.2.tgz",
       "dev": true
     },
     "babel-register": {
-      "version": "6.22.0",
-      "from": "babel-register@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-register/-/babel-register-6.22.0.tgz",
+      "version": "6.24.0",
+      "from": "babel-register@>=6.24.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-register/-/babel-register-6.24.0.tgz",
       "dev": true
     },
     "babel-runtime": {
-      "version": "6.22.0",
+      "version": "6.23.0",
       "from": "babel-runtime@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-runtime/-/babel-runtime-6.22.0.tgz",
+      "resolved": "https://registry.npmjs.org/babel-runtime/-/babel-runtime-6.23.0.tgz",
       "dev": true
     },
     "babel-template": {
-      "version": "6.22.0",
-      "from": "babel-template@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-template/-/babel-template-6.22.0.tgz",
+      "version": "6.23.0",
+      "from": "babel-template@>=6.23.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-template/-/babel-template-6.23.0.tgz",
       "dev": true
     },
     "babel-traverse": {
-      "version": "6.22.1",
-      "from": "babel-traverse@>=6.22.1 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-traverse/-/babel-traverse-6.22.1.tgz",
+      "version": "6.23.1",
+      "from": "babel-traverse@>=6.23.1 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-traverse/-/babel-traverse-6.23.1.tgz",
       "dev": true
     },
     "babel-types": {
-      "version": "6.22.0",
-      "from": "babel-types@>=6.22.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babel-types/-/babel-types-6.22.0.tgz",
+      "version": "6.23.0",
+      "from": "babel-types@>=6.23.0 <7.0.0",
+      "resolved": "https://registry.npmjs.org/babel-types/-/babel-types-6.23.0.tgz",
       "dev": true
     },
     "babylon": {
-      "version": "6.15.0",
+      "version": "6.16.1",
       "from": "babylon@>=6.11.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/babylon/-/babylon-6.15.0.tgz",
+      "resolved": "https://registry.npmjs.org/babylon/-/babylon-6.16.1.tgz",
       "dev": true
     },
     "balanced-match": {
@@ -417,6 +465,12 @@
       "resolved": "https://registry.npmjs.org/braces/-/braces-1.8.5.tgz",
       "dev": true
     },
+    "browserslist": {
+      "version": "1.7.7",
+      "from": "browserslist@>=1.4.0 <2.0.0",
+      "resolved": "https://registry.npmjs.org/browserslist/-/browserslist-1.7.7.tgz",
+      "dev": true
+    },
     "buffer-shims": {
       "version": "1.0.0",
       "from": "buffer-shims@>=1.0.0 <2.0.0",
@@ -441,6 +495,12 @@
       "resolved": "https://registry.npmjs.org/callsites/-/callsites-0.2.0.tgz",
       "dev": true
     },
+    "caniuse-db": {
+      "version": "1.0.30000640",
+      "from": "caniuse-db@>=1.0.30000639 <2.0.0",
+      "resolved": "https://registry.npmjs.org/caniuse-db/-/caniuse-db-1.0.30000640.tgz",
+      "dev": true
+    },
     "chalk": {
       "version": "1.1.3",
       "from": "chalk@>=1.1.0 <2.0.0",
@@ -491,7 +551,7 @@
     },
     "concat-stream": {
       "version": "1.6.0",
-      "from": "concat-stream@>=1.4.6 <2.0.0",
+      "from": "concat-stream@>=1.5.2 <2.0.0",
       "resolved": "https://registry.npmjs.org/concat-stream/-/concat-stream-1.6.0.tgz",
       "dev": true
     },
@@ -502,9 +562,9 @@
       "dev": true
     },
     "convert-source-map": {
-      "version": "1.3.0",
+      "version": "1.4.0",
       "from": "convert-source-map@>=1.1.0 <2.0.0",
-      "resolved": "https://registry.npmjs.org/convert-source-map/-/convert-source-map-1.3.0.tgz",
+      "resolved": "https://registry.npmjs.org/convert-source-map/-/convert-source-map-1.4.0.tgz",
       "dev": true
     },
     "core-js": {
@@ -520,9 +580,9 @@
       "dev": true
     },
     "d": {
-      "version": "0.1.1",
-      "from": "d@>=0.1.1 <0.2.0",
-      "resolved": "https://registry.npmjs.org/d/-/d-0.1.1.tgz",
+      "version": "1.0.0",
+      "from": "d@>=1.0.0 <2.0.0",
+      "resolved": "https://registry.npmjs.org/d/-/d-1.0.0.tgz",
       "dev": true
     },
     "damerau-levenshtein": {
@@ -532,9 +592,9 @@
       "dev": true
     },
     "debug": {
-      "version": "2.6.0",
+      "version": "2.6.3",
       "from": "debug@>=2.1.1 <3.0.0",
-      "resolved": "https://registry.npmjs.org/debug/-/debug-2.6.0.tgz",
+      "resolved": "https://registry.npmjs.org/debug/-/debug-2.6.3.tgz",
       "dev": true
     },
     "deep-is": {
@@ -562,15 +622,21 @@
       "dev": true
     },
     "doctrine": {
-      "version": "1.5.0",
-      "from": "doctrine@>=1.2.2 <2.0.0",
-      "resolved": "https://registry.npmjs.org/doctrine/-/doctrine-1.5.0.tgz",
+      "version": "2.0.0",
+      "from": "doctrine@>=2.0.0 <3.0.0",
+      "resolved": "https://registry.npmjs.org/doctrine/-/doctrine-2.0.0.tgz",
+      "dev": true
+    },
+    "electron-to-chromium": {
+      "version": "1.2.8",
+      "from": "electron-to-chromium@>=1.2.6 <2.0.0",
+      "resolved": "https://registry.npmjs.org/electron-to-chromium/-/electron-to-chromium-1.2.8.tgz",
       "dev": true
     },
     "emoji-regex": {
-      "version": "6.1.0",
+      "version": "6.4.1",
       "from": "emoji-regex@>=6.1.0 <7.0.0",
-      "resolved": "https://registry.npmjs.org/emoji-regex/-/emoji-regex-6.1.0.tgz",
+      "resolved": "https://registry.npmjs.org/emoji-regex/-/emoji-regex-6.4.1.tgz",
       "dev": true
     },
     "es-abstract": {
@@ -586,39 +652,39 @@
       "dev": true
     },
     "es5-ext": {
-      "version": "0.10.12",
-      "from": "es5-ext@>=0.10.11 <0.11.0",
-      "resolved": "https://registry.npmjs.org/es5-ext/-/es5-ext-0.10.12.tgz",
+      "version": "0.10.15",
+      "from": "es5-ext@>=0.10.14 <0.11.0",
+      "resolved": "https://registry.npmjs.org/es5-ext/-/es5-ext-0.10.15.tgz",
       "dev": true
     },
     "es6-iterator": {
-      "version": "2.0.0",
-      "from": "es6-iterator@>=2.0.0 <3.0.0",
-      "resolved": "https://registry.npmjs.org/es6-iterator/-/es6-iterator-2.0.0.tgz",
+      "version": "2.0.1",
+      "from": "es6-iterator@>=2.0.1 <2.1.0",
+      "resolved": "https://registry.npmjs.org/es6-iterator/-/es6-iterator-2.0.1.tgz",
       "dev": true
     },
     "es6-map": {
-      "version": "0.1.4",
+      "version": "0.1.5",
       "from": "es6-map@>=0.1.3 <0.2.0",
-      "resolved": "https://registry.npmjs.org/es6-map/-/es6-map-0.1.4.tgz",
+      "resolved": "https://registry.npmjs.org/es6-map/-/es6-map-0.1.5.tgz",
       "dev": true
     },
     "es6-set": {
-      "version": "0.1.4",
-      "from": "es6-set@>=0.1.3 <0.2.0",
-      "resolved": "https://registry.npmjs.org/es6-set/-/es6-set-0.1.4.tgz",
+      "version": "0.1.5",
+      "from": "es6-set@>=0.1.5 <0.2.0",
+      "resolved": "https://registry.npmjs.org/es6-set/-/es6-set-0.1.5.tgz",
       "dev": true
     },
     "es6-symbol": {
-      "version": "3.1.0",
-      "from": "es6-symbol@>=3.1.0 <3.2.0",
-      "resolved": "https://registry.npmjs.org/es6-symbol/-/es6-symbol-3.1.0.tgz",
+      "version": "3.1.1",
+      "from": "es6-symbol@>=3.1.1 <3.2.0",
+      "resolved": "https://registry.npmjs.org/es6-symbol/-/es6-symbol-3.1.1.tgz",
       "dev": true
     },
     "es6-weak-map": {
-      "version": "2.0.1",
+      "version": "2.0.2",
       "from": "es6-weak-map@>=2.0.1 <3.0.0",
-      "resolved": "https://registry.npmjs.org/es6-weak-map/-/es6-weak-map-2.0.1.tgz",
+      "resolved": "https://registry.npmjs.org/es6-weak-map/-/es6-weak-map-2.0.2.tgz",
       "dev": true
     },
     "escape-string-regexp": {
@@ -634,9 +700,9 @@
       "dev": true
     },
     "eslint": {
-      "version": "3.15.0",
-      "from": "eslint@3.15.0",
-      "resolved": "https://registry.npmjs.org/eslint/-/eslint-3.15.0.tgz",
+      "version": "3.18.0",
+      "from": "eslint@3.18.0",
+      "resolved": "https://registry.npmjs.org/eslint/-/eslint-3.18.0.tgz",
       "dev": true
     },
     "eslint-config-airbnb": {
@@ -646,9 +712,9 @@
       "dev": true
     },
     "eslint-config-airbnb-base": {
-      "version": "11.1.0",
+      "version": "11.1.1",
       "from": "eslint-config-airbnb-base@>=11.1.0 <12.0.0",
-      "resolved": "https://registry.npmjs.org/eslint-config-airbnb-base/-/eslint-config-airbnb-base-11.1.0.tgz",
+      "resolved": "https://registry.npmjs.org/eslint-config-airbnb-base/-/eslint-config-airbnb-base-11.1.1.tgz",
       "dev": true
     },
     "eslint-import-resolver-node": {
@@ -681,7 +747,15 @@
       "version": "2.2.0",
       "from": "eslint-plugin-import@2.2.0",
       "resolved": "https://registry.npmjs.org/eslint-plugin-import/-/eslint-plugin-import-2.2.0.tgz",
-      "dev": true
+      "dev": true,
+      "dependencies": {
+        "doctrine": {
+          "version": "1.5.0",
+          "from": "doctrine@1.5.0",
+          "resolved": "https://registry.npmjs.org/doctrine/-/doctrine-1.5.0.tgz",
+          "dev": true
+        }
+      }
     },
     "eslint-plugin-jsx-a11y": {
       "version": "4.0.0",
@@ -690,10 +764,18 @@
       "dev": true
     },
     "eslint-plugin-react": {
-      "version": "6.9.0",
-      "from": "eslint-plugin-react@6.9.0",
-      "resolved": "https://registry.npmjs.org/eslint-plugin-react/-/eslint-plugin-react-6.9.0.tgz",
-      "dev": true
+      "version": "6.10.3",
+      "from": "eslint-plugin-react@6.10.3",
+      "resolved": "https://registry.npmjs.org/eslint-plugin-react/-/eslint-plugin-react-6.10.3.tgz",
+      "dev": true,
+      "dependencies": {
+        "doctrine": {
+          "version": "1.5.0",
+          "from": "doctrine@>=1.2.2 <2.0.0",
+          "resolved": "https://registry.npmjs.org/doctrine/-/doctrine-1.5.0.tgz",
+          "dev": true
+        }
+      }
     },
     "espree": {
       "version": "3.4.0",
@@ -702,9 +784,15 @@
       "dev": true
     },
     "esprima": {
-      "version": "2.7.3",
-      "from": "esprima@>=2.6.0 <3.0.0",
-      "resolved": "https://registry.npmjs.org/esprima/-/esprima-2.7.3.tgz",
+      "version": "3.1.3",
+      "from": "esprima@>=3.1.1 <4.0.0",
+      "resolved": "https://registry.npmjs.org/esprima/-/esprima-3.1.3.tgz",
+      "dev": true
+    },
+    "esquery": {
+      "version": "1.0.0",
+      "from": "esquery@>=1.0.0 <2.0.0",
+      "resolved": "https://registry.npmjs.org/esquery/-/esquery-1.0.0.tgz",
       "dev": true
     },
     "esrecurse": {
@@ -734,9 +822,9 @@
       "dev": true
     },
     "event-emitter": {
-      "version": "0.3.4",
-      "from": "event-emitter@>=0.3.4 <0.4.0",
-      "resolved": "https://registry.npmjs.org/event-emitter/-/event-emitter-0.3.4.tgz",
+      "version": "0.3.5",
+      "from": "event-emitter@>=0.3.5 <0.4.0",
+      "resolved": "https://registry.npmjs.org/event-emitter/-/event-emitter-0.3.5.tgz",
       "dev": true
     },
     "exit-hook": {
@@ -806,15 +894,15 @@
       "dev": true
     },
     "for-in": {
-      "version": "0.1.6",
-      "from": "for-in@>=0.1.5 <0.2.0",
-      "resolved": "https://registry.npmjs.org/for-in/-/for-in-0.1.6.tgz",
+      "version": "1.0.2",
+      "from": "for-in@>=1.0.1 <2.0.0",
+      "resolved": "https://registry.npmjs.org/for-in/-/for-in-1.0.2.tgz",
       "dev": true
     },
     "for-own": {
-      "version": "0.1.4",
+      "version": "0.1.5",
       "from": "for-own@>=0.1.4 <0.2.0",
-      "resolved": "https://registry.npmjs.org/for-own/-/for-own-0.1.4.tgz",
+      "resolved": "https://registry.npmjs.org/for-own/-/for-own-0.1.5.tgz",
       "dev": true
     },
     "foreach": {
@@ -830,23 +918,23 @@
       "dev": true
     },
     "fsevents": {
-      "version": "1.0.17",
+      "version": "1.1.1",
       "from": "fsevents@>=1.0.0 <2.0.0",
-      "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-1.0.17.tgz",
+      "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-1.1.1.tgz",
       "dev": true,
       "optional": true,
       "dependencies": {
         "abbrev": {
-          "version": "1.0.9",
+          "version": "1.1.0",
           "from": "abbrev@>=1.0.0 <2.0.0",
-          "resolved": "https://registry.npmjs.org/abbrev/-/abbrev-1.0.9.tgz",
+          "resolved": "https://registry.npmjs.org/abbrev/-/abbrev-1.1.0.tgz",
           "dev": true,
           "optional": true
         },
         "ansi-regex": {
-          "version": "2.0.0",
+          "version": "2.1.1",
           "from": "ansi-regex@>=2.0.0 <3.0.0",
-          "resolved": "https://registry.npmjs.org/ansi-regex/-/ansi-regex-2.0.0.tgz",
+          "resolved": "https://registry.npmjs.org/ansi-regex/-/ansi-regex-2.1.1.tgz",
           "dev": true
         },
         "ansi-styles": {
@@ -857,9 +945,9 @@
           "optional": true
         },
         "aproba": {
-          "version": "1.0.4",
+          "version": "1.1.1",
           "from": "aproba@>=1.0.3 <2.0.0",
-          "resolved": "https://registry.npmjs.org/aproba/-/aproba-1.0.4.tgz",
+          "resolved": "https://registry.npmjs.org/aproba/-/aproba-1.1.1.tgz",
           "dev": true,
           "optional": true
         },
@@ -899,9 +987,9 @@
           "optional": true
         },
         "aws4": {
-          "version": "1.5.0",
+          "version": "1.6.0",
           "from": "aws4@>=1.2.1 <2.0.0",
-          "resolved": "https://registry.npmjs.org/aws4/-/aws4-1.5.0.tgz",
+          "resolved": "https://registry.npmjs.org/aws4/-/aws4-1.6.0.tgz",
           "dev": true,
           "optional": true
         },
@@ -912,9 +1000,9 @@
           "dev": true
         },
         "bcrypt-pbkdf": {
-          "version": "1.0.0",
+          "version": "1.0.1",
           "from": "bcrypt-pbkdf@>=1.0.0 <2.0.0",
-          "resolved": "https://registry.npmjs.org/bcrypt-pbkdf/-/bcrypt-pbkdf-1.0.0.tgz",
+          "resolved": "https://registry.npmjs.org/bcrypt-pbkdf/-/bcrypt-pbkdf-1.0.1.tgz",
           "dev": true,
           "optional": true
         },
@@ -954,16 +1042,7 @@
           "from": "chalk@>=1.1.1 <2.0.0",
           "resolved": "https://registry.npmjs.org/chalk/-/chalk-1.1.3.tgz",
           "dev": true,
-          "optional": true,
-          "dependencies": {
-            "supports-color": {
-              "version": "2.0.0",
-              "from": "supports-color@>=2.0.0 <3.0.0",
-              "resolved": "https://registry.npmjs.org/supports-color/-/supports-color-2.0.0.tgz",
-              "dev": true,
-              "optional": true
-            }
-          }
+          "optional": true
         },
         "code-point-at": {
           "version": "1.1.0",
@@ -1113,9 +1192,9 @@
           "optional": true
         },
         "gauge": {
-          "version": "2.7.2",
+          "version": "2.7.3",
           "from": "gauge@>=2.7.1 <2.8.0",
-          "resolved": "https://registry.npmjs.org/gauge/-/gauge-2.7.2.tgz",
+          "resolved": "https://registry.npmjs.org/gauge/-/gauge-2.7.3.tgz",
           "dev": true,
           "optional": true
         },
@@ -1276,9 +1355,9 @@
           "optional": true
         },
         "jsbn": {
-          "version": "0.1.0",
+          "version": "0.1.1",
           "from": "jsbn@>=0.1.0 <0.2.0",
-          "resolved": "https://registry.npmjs.org/jsbn/-/jsbn-0.1.0.tgz",
+          "resolved": "https://registry.npmjs.org/jsbn/-/jsbn-0.1.1.tgz",
           "dev": true,
           "optional": true
         },
@@ -1311,15 +1390,15 @@
           "optional": true
         },
         "mime-db": {
-          "version": "1.25.0",
-          "from": "mime-db@>=1.25.0 <1.26.0",
-          "resolved": "https://registry.npmjs.org/mime-db/-/mime-db-1.25.0.tgz",
+          "version": "1.26.0",
+          "from": "mime-db@>=1.26.0 <1.27.0",
+          "resolved": "https://registry.npmjs.org/mime-db/-/mime-db-1.26.0.tgz",
           "dev": true
         },
         "mime-types": {
-          "version": "2.1.13",
+          "version": "2.1.14",
           "from": "mime-types@>=2.1.7 <2.2.0",
-          "resolved": "https://registry.npmjs.org/mime-types/-/mime-types-2.1.13.tgz",
+          "resolved": "https://registry.npmjs.org/mime-types/-/mime-types-2.1.14.tgz",
           "dev": true
         },
         "minimatch": {
@@ -1348,9 +1427,9 @@
           "optional": true
         },
         "node-pre-gyp": {
-          "version": "0.6.32",
+          "version": "0.6.33",
           "from": "node-pre-gyp@>=0.6.29 <0.7.0",
-          "resolved": "https://registry.npmjs.org/node-pre-gyp/-/node-pre-gyp-0.6.32.tgz",
+          "resolved": "https://registry.npmjs.org/node-pre-gyp/-/node-pre-gyp-0.6.33.tgz",
           "dev": true,
           "optional": true
         },
@@ -1382,9 +1461,9 @@
           "optional": true
         },
         "object-assign": {
-          "version": "4.1.0",
+          "version": "4.1.1",
           "from": "object-assign@>=4.1.0 <5.0.0",
-          "resolved": "https://registry.npmjs.org/object-assign/-/object-assign-4.1.0.tgz",
+          "resolved": "https://registry.npmjs.org/object-assign/-/object-assign-4.1.1.tgz",
           "dev": true,
           "optional": true
         },
@@ -1428,16 +1507,16 @@
           "optional": true
         },
         "qs": {
-          "version": "6.3.0",
+          "version": "6.3.1",
           "from": "qs@>=6.3.0 <6.4.0",
-          "resolved": "https://registry.npmjs.org/qs/-/qs-6.3.0.tgz",
+          "resolved": "https://registry.npmjs.org/qs/-/qs-6.3.1.tgz",
           "dev": true,
           "optional": true
         },
         "rc": {
-          "version": "1.1.6",
+          "version": "1.1.7",
           "from": "rc@>=1.1.6 <1.2.0",
-          "resolved": "https://registry.npmjs.org/rc/-/rc-1.1.6.tgz",
+          "resolved": "https://registry.npmjs.org/rc/-/rc-1.1.7.tgz",
           "dev": true,
           "optional": true,
           "dependencies": {
@@ -1499,9 +1578,9 @@
           "optional": true
         },
         "sshpk": {
-          "version": "1.10.1",
+          "version": "1.10.2",
           "from": "sshpk@>=1.7.0 <2.0.0",
-          "resolved": "https://registry.npmjs.org/sshpk/-/sshpk-1.10.1.tgz",
+          "resolved": "https://registry.npmjs.org/sshpk/-/sshpk-1.10.2.tgz",
           "dev": true,
           "optional": true,
           "dependencies": {
@@ -1540,16 +1619,16 @@
           "dev": true
         },
         "strip-json-comments": {
-          "version": "1.0.4",
-          "from": "strip-json-comments@>=1.0.4 <1.1.0",
-          "resolved": "https://registry.npmjs.org/strip-json-comments/-/strip-json-comments-1.0.4.tgz",
+          "version": "2.0.1",
+          "from": "strip-json-comments@>=2.0.1 <2.1.0",
+          "resolved": "https://registry.npmjs.org/strip-json-comments/-/strip-json-comments-2.0.1.tgz",
           "dev": true,
           "optional": true
         },
         "supports-color": {
-          "version": "0.2.0",
-          "from": "supports-color@>=0.2.0 <0.3.0",
-          "resolved": "https://registry.npmjs.org/supports-color/-/supports-color-0.2.0.tgz",
+          "version": "2.0.0",
+          "from": "supports-color@>=2.0.0 <3.0.0",
+          "resolved": "https://registry.npmjs.org/supports-color/-/supports-color-2.0.0.tgz",
           "dev": true,
           "optional": true
         },
@@ -1689,9 +1768,9 @@
       "dev": true
     },
     "globals": {
-      "version": "9.14.0",
+      "version": "9.16.0",
       "from": "globals@>=9.0.0 <10.0.0",
-      "resolved": "https://registry.npmjs.org/globals/-/globals-9.14.0.tgz",
+      "resolved": "https://registry.npmjs.org/globals/-/globals-9.16.0.tgz",
       "dev": true
     },
     "globby": {
@@ -1725,9 +1804,9 @@
       "dev": true
     },
     "ignore": {
-      "version": "3.2.2",
+      "version": "3.2.6",
       "from": "ignore@>=3.2.0 <4.0.0",
-      "resolved": "https://registry.npmjs.org/ignore/-/ignore-3.2.2.tgz",
+      "resolved": "https://registry.npmjs.org/ignore/-/ignore-3.2.6.tgz",
       "dev": true
     },
     "imurmurhash": {
@@ -1773,9 +1852,9 @@
       "dev": true
     },
     "is-buffer": {
-      "version": "1.1.4",
+      "version": "1.1.5",
       "from": "is-buffer@>=1.0.2 <2.0.0",
-      "resolved": "https://registry.npmjs.org/is-buffer/-/is-buffer-1.1.4.tgz",
+      "resolved": "https://registry.npmjs.org/is-buffer/-/is-buffer-1.1.5.tgz",
       "dev": true
     },
     "is-callable": {
@@ -1833,9 +1912,9 @@
       "dev": true
     },
     "is-my-json-valid": {
-      "version": "2.15.0",
+      "version": "2.16.0",
       "from": "is-my-json-valid@>=2.10.0 <3.0.0",
-      "resolved": "https://registry.npmjs.org/is-my-json-valid/-/is-my-json-valid-2.15.0.tgz",
+      "resolved": "https://registry.npmjs.org/is-my-json-valid/-/is-my-json-valid-2.16.0.tgz",
       "dev": true
     },
     "is-number": {
@@ -1881,9 +1960,9 @@
       "dev": true
     },
     "is-regex": {
-      "version": "1.0.3",
+      "version": "1.0.4",
       "from": "is-regex@>=1.0.3 <2.0.0",
-      "resolved": "https://registry.npmjs.org/is-regex/-/is-regex-1.0.3.tgz",
+      "resolved": "https://registry.npmjs.org/is-regex/-/is-regex-1.0.4.tgz",
       "dev": true
     },
     "is-resolvable": {
@@ -1917,9 +1996,9 @@
       "dev": true
     },
     "js-yaml": {
-      "version": "3.7.0",
+      "version": "3.8.2",
       "from": "js-yaml@>=3.5.1 <4.0.0",
-      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-3.7.0.tgz",
+      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-3.8.2.tgz",
       "dev": true
     },
     "jsesc": {
@@ -2061,6 +2140,12 @@
       "resolved": "https://registry.npmjs.org/object-keys/-/object-keys-1.0.11.tgz",
       "dev": true
     },
+    "object.assign": {
+      "version": "4.0.4",
+      "from": "object.assign@>=4.0.4 <5.0.0",
+      "resolved": "https://registry.npmjs.org/object.assign/-/object.assign-4.0.4.tgz",
+      "dev": true
+    },
     "object.omit": {
       "version": "2.0.1",
       "from": "object.omit@>=2.0.0 <3.0.0",
@@ -2121,6 +2206,12 @@
       "resolved": "https://registry.npmjs.org/path-is-inside/-/path-is-inside-1.0.2.tgz",
       "dev": true
     },
+    "path-parse": {
+      "version": "1.0.5",
+      "from": "path-parse@>=1.0.5 <2.0.0",
+      "resolved": "https://registry.npmjs.org/path-parse/-/path-parse-1.0.5.tgz",
+      "dev": true
+    },
     "pify": {
       "version": "2.3.0",
       "from": "pify@>=2.0.0 <3.0.0",
@@ -2194,9 +2285,9 @@
       "dev": true
     },
     "readable-stream": {
-      "version": "2.2.2",
+      "version": "2.2.6",
       "from": "readable-stream@>=2.0.2 <3.0.0",
-      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-2.2.2.tgz",
+      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-2.2.6.tgz",
       "dev": true
     },
     "readdirp": {
@@ -2224,9 +2315,9 @@
       "dev": true
     },
     "regenerator-runtime": {
-      "version": "0.10.1",
+      "version": "0.10.3",
       "from": "regenerator-runtime@>=0.10.0 <0.11.0",
-      "resolved": "https://registry.npmjs.org/regenerator-runtime/-/regenerator-runtime-0.10.1.tgz",
+      "resolved": "https://registry.npmjs.org/regenerator-runtime/-/regenerator-runtime-0.10.3.tgz",
       "dev": true
     },
     "regenerator-transform": {
@@ -2292,9 +2383,9 @@
       "dev": true
     },
     "resolve": {
-      "version": "1.2.0",
+      "version": "1.3.2",
       "from": "resolve@>=1.1.6 <2.0.0",
-      "resolved": "https://registry.npmjs.org/resolve/-/resolve-1.2.0.tgz",
+      "resolved": "https://registry.npmjs.org/resolve/-/resolve-1.3.2.tgz",
       "dev": true
     },
     "resolve-from": {
@@ -2310,9 +2401,9 @@
       "dev": true
     },
     "rimraf": {
-      "version": "2.5.4",
+      "version": "2.6.1",
       "from": "rimraf@>=2.2.8 <3.0.0",
-      "resolved": "https://registry.npmjs.org/rimraf/-/rimraf-2.5.4.tgz",
+      "resolved": "https://registry.npmjs.org/rimraf/-/rimraf-2.6.1.tgz",
       "dev": true
     },
     "run-async": {
@@ -2334,9 +2425,9 @@
       "dev": true
     },
     "shelljs": {
-      "version": "0.7.6",
+      "version": "0.7.7",
       "from": "shelljs@>=0.7.5 <0.8.0",
-      "resolved": "https://registry.npmjs.org/shelljs/-/shelljs-0.7.6.tgz",
+      "resolved": "https://registry.npmjs.org/shelljs/-/shelljs-0.7.7.tgz",
       "dev": true
     },
     "slash": {
@@ -2358,9 +2449,9 @@
       "dev": true
     },
     "source-map-support": {
-      "version": "0.4.11",
+      "version": "0.4.14",
       "from": "source-map-support@>=0.4.2 <0.5.0",
-      "resolved": "https://registry.npmjs.org/source-map-support/-/source-map-support-0.4.11.tgz",
+      "resolved": "https://registry.npmjs.org/source-map-support/-/source-map-support-0.4.14.tgz",
       "dev": true
     },
     "sprintf-js": {
@@ -2443,6 +2534,12 @@
       "resolved": "https://registry.npmjs.org/to-fast-properties/-/to-fast-properties-1.0.2.tgz",
       "dev": true
     },
+    "trim-right": {
+      "version": "1.0.1",
+      "from": "trim-right@>=1.0.1 <2.0.0",
+      "resolved": "https://registry.npmjs.org/trim-right/-/trim-right-1.0.1.tgz",
+      "dev": true
+    },
     "tryit": {
       "version": "1.0.3",
       "from": "tryit@>=1.0.1 <2.0.0",
diff -u b/core/package.json b/core/package.json
--- b/core/package.json
+++ b/core/package.json
@@ -9,19 +9,29 @@
     "lint:core-js": "node ./node_modules/eslint/bin/eslint.js --ext=.es6.js . --fix || exit 0"
   },
   "devDependencies": {
-    "babel-core": "6.22.1",
-    "babel-preset-es2015": "6.22.0",
+    "babel-core": "6.24.0",
+    "babel-preset-env": "1.2.2",
     "chokidar": "1.6.1",
-    "eslint": "3.15.0",
+    "eslint": "3.18.0",
     "eslint-config-airbnb": "14.1.0",
     "eslint-plugin-import": "2.2.0",
     "eslint-plugin-jsx-a11y": "4.0.0",
-    "eslint-plugin-react": "6.9.0",
+    "eslint-plugin-react": "6.10.3",
     "glob": "7.1.1"
   },
   "babel": {
     "presets": [
-      "es2015"
+      [
+        "env",
+        {
+          "targets": {
+            "browsers": [
+              "last 2 versions",
+              "ie >= 9"
+            ]
+          }
+        }
+      ]
     ]
   }
 }
only in patch2:
unchanged:
--- a/core/.eslintignore
+++ b/core/.eslintignore
@@ -2,3 +2,5 @@ assets/vendor/**/*
 modules/locale/tests/locale_test.js
 node_modules/**/*
 **/js_test_files/**/*
+*.js
+!*.es6.js
only in patch2:
unchanged:
--- a/core/scripts/js/babel-es6-build.js
+++ b/core/scripts/js/babel-es6-build.js
@@ -33,10 +33,12 @@ const changedOrAdded = (filePath) => {
     // we've requested for a sourcemap to be written to disk
     let mapLoc = `${fileName}.js.map`;
 
-    fs.writeFile(mapLoc, JSON.stringify(result.map));
-    fs.writeFile(`${fileName}.js`, addSourceMappingUrl(result.code, mapLoc));
-
     log(`'${filePath}' is being processed.`);
+    fs.writeFile(mapLoc, JSON.stringify(result.map), () => {
+      fs.writeFile(`${fileName}.js`, addSourceMappingUrl(result.code, mapLoc), () => {
+        log(`'${filePath}' is finished.`);
+      });
+    });
   });
 };