diff --git a/karma.conf.js b/karma.conf.js
index c77b0d9a..d1f2ea64 100644
--- a/karma.conf.js
+++ b/karma.conf.js
@@ -4,10 +4,12 @@ module.exports = function(config) {
   const customLaunchers = {};
   let browsers = [];
   let useSauce = false;
+  let transpile = false;
 
   // use Sauce when running on Travis
   if (process.env.TRAVIS_JOB_NUMBER) {
     useSauce = true;
+    transpile = true;
   }
 
   if (useSauce && process.env.TEST_BROWSER_NAME && process.env.TEST_BROWSER_NAME != 'PhantomJS') {
@@ -97,6 +99,7 @@ module.exports = function(config) {
 
     babelPreprocessor: {
       options: {
+        presets: transpile ? ['es2015'] : [],
         plugins: ['transform-es2015-modules-amd', 'syntax-dynamic-import'],
         sourceMap: 'inline',
       },
diff --git a/package-lock.json b/package-lock.json
index ef56a931..327853a2 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -412,6 +412,53 @@
         "trim-right": "1.0.1"
       }
     },
+    "babel-helper-call-delegate": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-helper-call-delegate/-/babel-helper-call-delegate-6.24.1.tgz",
+      "integrity": "sha1-7Oaqzdx25Bw0YfiL/Fdb0Nqi340=",
+      "dev": true,
+      "requires": {
+        "babel-helper-hoist-variables": "6.24.1",
+        "babel-runtime": "6.26.0",
+        "babel-traverse": "6.26.0",
+        "babel-types": "6.26.0"
+      }
+    },
+    "babel-helper-define-map": {
+      "version": "6.26.0",
+      "resolved": "https://registry.npmjs.org/babel-helper-define-map/-/babel-helper-define-map-6.26.0.tgz",
+      "integrity": "sha1-pfVtq0GiX5fstJjH66ypgZ+Vvl8=",
+      "dev": true,
+      "requires": {
+        "babel-helper-function-name": "6.24.1",
+        "babel-runtime": "6.26.0",
+        "babel-types": "6.26.0",
+        "lodash": "4.17.4"
+      }
+    },
+    "babel-helper-function-name": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-helper-function-name/-/babel-helper-function-name-6.24.1.tgz",
+      "integrity": "sha1-00dbjAPtmCQqJbSDUasYOZ01gKk=",
+      "dev": true,
+      "requires": {
+        "babel-helper-get-function-arity": "6.24.1",
+        "babel-runtime": "6.26.0",
+        "babel-template": "6.26.0",
+        "babel-traverse": "6.26.0",
+        "babel-types": "6.26.0"
+      }
+    },
+    "babel-helper-get-function-arity": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-helper-get-function-arity/-/babel-helper-get-function-arity-6.24.1.tgz",
+      "integrity": "sha1-j3eCqpNAfEHTqlCQj4mwMbG2hT0=",
+      "dev": true,
+      "requires": {
+        "babel-runtime": "6.26.0",
+        "babel-types": "6.26.0"
+      }
+    },
     "babel-helper-hoist-variables": {
       "version": "6.24.1",
       "resolved": "https://registry.npmjs.org/babel-helper-hoist-variables/-/babel-helper-hoist-variables-6.24.1.tgz",
@@ -422,6 +469,41 @@
         "babel-types": "6.26.0"
       }
     },
+    "babel-helper-optimise-call-expression": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-helper-optimise-call-expression/-/babel-helper-optimise-call-expression-6.24.1.tgz",
+      "integrity": "sha1-96E0J7qfc/j0+pk8VKl4gtEkQlc=",
+      "dev": true,
+      "requires": {
+        "babel-runtime": "6.26.0",
+        "babel-types": "6.26.0"
+      }
+    },
+    "babel-helper-regex": {
+      "version": "6.26.0",
+      "resolved": "https://registry.npmjs.org/babel-helper-regex/-/babel-helper-regex-6.26.0.tgz",
+      "integrity": "sha1-MlxZ+QL4LyS3T6zu0DY5VPZJXnI=",
+      "dev": true,
+      "requires": {
+        "babel-runtime": "6.26.0",
+        "babel-types": "6.26.0",
+        "lodash": "4.17.4"
+      }
+    },
+    "babel-helper-replace-supers": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-helper-replace-supers/-/babel-helper-replace-supers-6.24.1.tgz",
+      "integrity": "sha1-v22/5Dk40XNpohPKiov3S2qQqxo=",
+      "dev": true,
+      "requires": {
+        "babel-helper-optimise-call-expression": "6.24.1",
+        "babel-messages": "6.23.0",
+        "babel-runtime": "6.26.0",
+        "babel-template": "6.26.0",
+        "babel-traverse": "6.26.0",
+        "babel-types": "6.26.0"
+      }
+    },
     "babel-helpers": {
       "version": "6.24.1",
       "resolved": "https://registry.npmjs.org/babel-helpers/-/babel-helpers-6.24.1.tgz",
@@ -447,6 +529,15 @@
       "integrity": "sha1-mumh9KjcZ/DN7E9K7aHkOl/2XiU=",
       "dev": true
     },
+    "babel-plugin-check-es2015-constants": {
+      "version": "6.22.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-check-es2015-constants/-/babel-plugin-check-es2015-constants-6.22.0.tgz",
+      "integrity": "sha1-NRV7EBQm/S/9PaP3XH0ekYNbv4o=",
+      "dev": true,
+      "requires": {
+        "babel-runtime": "6.26.0"
+      }
+    },
     "babel-plugin-import-redirect": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/babel-plugin-import-redirect/-/babel-plugin-import-redirect-1.1.0.tgz",
@@ -463,6 +554,112 @@
       "integrity": "sha1-jWomIpyDdFqZgqRBBRVyyqF5sdo=",
       "dev": true
     },
+    "babel-plugin-transform-es2015-arrow-functions": {
+      "version": "6.22.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-arrow-functions/-/babel-plugin-transform-es2015-arrow-functions-6.22.0.tgz",
+      "integrity": "sha1-RSaSy3EdX3ncf4XkQM5BufJE0iE=",
+      "dev": true,
+      "requires": {
+        "babel-runtime": "6.26.0"
+      }
+    },
+    "babel-plugin-transform-es2015-block-scoped-functions": {
+      "version": "6.22.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-block-scoped-functions/-/babel-plugin-transform-es2015-block-scoped-functions-6.22.0.tgz",
+      "integrity": "sha1-u8UbSflk1wy42OC5ToICRs46YUE=",
+      "dev": true,
+      "requires": {
+        "babel-runtime": "6.26.0"
+      }
+    },
+    "babel-plugin-transform-es2015-block-scoping": {
+      "version": "6.26.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-block-scoping/-/babel-plugin-transform-es2015-block-scoping-6.26.0.tgz",
+      "integrity": "sha1-1w9SmcEwjQXBL0Y4E7CgnnOxiV8=",
+      "dev": true,
+      "requires": {
+        "babel-runtime": "6.26.0",
+        "babel-template": "6.26.0",
+        "babel-traverse": "6.26.0",
+        "babel-types": "6.26.0",
+        "lodash": "4.17.4"
+      }
+    },
+    "babel-plugin-transform-es2015-classes": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-classes/-/babel-plugin-transform-es2015-classes-6.24.1.tgz",
+      "integrity": "sha1-WkxYpQyclGHlZLSyo7+ryXolhNs=",
+      "dev": true,
+      "requires": {
+        "babel-helper-define-map": "6.26.0",
+        "babel-helper-function-name": "6.24.1",
+        "babel-helper-optimise-call-expression": "6.24.1",
+        "babel-helper-replace-supers": "6.24.1",
+        "babel-messages": "6.23.0",
+        "babel-runtime": "6.26.0",
+        "babel-template": "6.26.0",
+        "babel-traverse": "6.26.0",
+        "babel-types": "6.26.0"
+      }
+    },
+    "babel-plugin-transform-es2015-computed-properties": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-computed-properties/-/babel-plugin-transform-es2015-computed-properties-6.24.1.tgz",
+      "integrity": "sha1-b+Ko0WiV1WNPTNmZttNICjCBWbM=",
+      "dev": true,
+      "requires": {
+        "babel-runtime": "6.26.0",
+        "babel-template": "6.26.0"
+      }
+    },
+    "babel-plugin-transform-es2015-destructuring": {
+      "version": "6.23.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-destructuring/-/babel-plugin-transform-es2015-destructuring-6.23.0.tgz",
+      "integrity": "sha1-mXux8auWf2gtKwh2/jWNYOdlxW0=",
+      "dev": true,
+      "requires": {
+        "babel-runtime": "6.26.0"
+      }
+    },
+    "babel-plugin-transform-es2015-duplicate-keys": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-duplicate-keys/-/babel-plugin-transform-es2015-duplicate-keys-6.24.1.tgz",
+      "integrity": "sha1-c+s9MQypaePvnskcU3QabxV2Qj4=",
+      "dev": true,
+      "requires": {
+        "babel-runtime": "6.26.0",
+        "babel-types": "6.26.0"
+      }
+    },
+    "babel-plugin-transform-es2015-for-of": {
+      "version": "6.23.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-for-of/-/babel-plugin-transform-es2015-for-of-6.23.0.tgz",
+      "integrity": "sha1-9HyVsrYT3x0+zC/bdXNiPHUkhpE=",
+      "dev": true,
+      "requires": {
+        "babel-runtime": "6.26.0"
+      }
+    },
+    "babel-plugin-transform-es2015-function-name": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-function-name/-/babel-plugin-transform-es2015-function-name-6.24.1.tgz",
+      "integrity": "sha1-g0yJhTvDaxrw86TF26qU/Y6sqos=",
+      "dev": true,
+      "requires": {
+        "babel-helper-function-name": "6.24.1",
+        "babel-runtime": "6.26.0",
+        "babel-types": "6.26.0"
+      }
+    },
+    "babel-plugin-transform-es2015-literals": {
+      "version": "6.22.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-literals/-/babel-plugin-transform-es2015-literals-6.22.0.tgz",
+      "integrity": "sha1-T1SgLWzWbPkVKAAZox0xklN3yi4=",
+      "dev": true,
+      "requires": {
+        "babel-runtime": "6.26.0"
+      }
+    },
     "babel-plugin-transform-es2015-modules-amd": {
       "version": "6.24.1",
       "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-modules-amd/-/babel-plugin-transform-es2015-modules-amd-6.24.1.tgz",
@@ -508,6 +705,98 @@
         "babel-template": "6.26.0"
       }
     },
+    "babel-plugin-transform-es2015-object-super": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-object-super/-/babel-plugin-transform-es2015-object-super-6.24.1.tgz",
+      "integrity": "sha1-JM72muIcuDp/hgPa0CH1cusnj40=",
+      "dev": true,
+      "requires": {
+        "babel-helper-replace-supers": "6.24.1",
+        "babel-runtime": "6.26.0"
+      }
+    },
+    "babel-plugin-transform-es2015-parameters": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-parameters/-/babel-plugin-transform-es2015-parameters-6.24.1.tgz",
+      "integrity": "sha1-V6w1GrScrxSpfNE7CfZv3wpiXys=",
+      "dev": true,
+      "requires": {
+        "babel-helper-call-delegate": "6.24.1",
+        "babel-helper-get-function-arity": "6.24.1",
+        "babel-runtime": "6.26.0",
+        "babel-template": "6.26.0",
+        "babel-traverse": "6.26.0",
+        "babel-types": "6.26.0"
+      }
+    },
+    "babel-plugin-transform-es2015-shorthand-properties": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-shorthand-properties/-/babel-plugin-transform-es2015-shorthand-properties-6.24.1.tgz",
+      "integrity": "sha1-JPh11nIch2YbvZmkYi5R8U3jiqA=",
+      "dev": true,
+      "requires": {
+        "babel-runtime": "6.26.0",
+        "babel-types": "6.26.0"
+      }
+    },
+    "babel-plugin-transform-es2015-spread": {
+      "version": "6.22.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-spread/-/babel-plugin-transform-es2015-spread-6.22.0.tgz",
+      "integrity": "sha1-1taKmfia7cRTbIGlQujdnxdG+NE=",
+      "dev": true,
+      "requires": {
+        "babel-runtime": "6.26.0"
+      }
+    },
+    "babel-plugin-transform-es2015-sticky-regex": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-sticky-regex/-/babel-plugin-transform-es2015-sticky-regex-6.24.1.tgz",
+      "integrity": "sha1-AMHNsaynERLN8M9hJsLta0V8zbw=",
+      "dev": true,
+      "requires": {
+        "babel-helper-regex": "6.26.0",
+        "babel-runtime": "6.26.0",
+        "babel-types": "6.26.0"
+      }
+    },
+    "babel-plugin-transform-es2015-template-literals": {
+      "version": "6.22.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-template-literals/-/babel-plugin-transform-es2015-template-literals-6.22.0.tgz",
+      "integrity": "sha1-qEs0UPfp+PH2g51taH2oS7EjbY0=",
+      "dev": true,
+      "requires": {
+        "babel-runtime": "6.26.0"
+      }
+    },
+    "babel-plugin-transform-es2015-typeof-symbol": {
+      "version": "6.23.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-typeof-symbol/-/babel-plugin-transform-es2015-typeof-symbol-6.23.0.tgz",
+      "integrity": "sha1-3sCfHN3/lLUqxz1QXITfWdzOs3I=",
+      "dev": true,
+      "requires": {
+        "babel-runtime": "6.26.0"
+      }
+    },
+    "babel-plugin-transform-es2015-unicode-regex": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-unicode-regex/-/babel-plugin-transform-es2015-unicode-regex-6.24.1.tgz",
+      "integrity": "sha1-04sS9C6nMj9yk4fxinxa4frrNek=",
+      "dev": true,
+      "requires": {
+        "babel-helper-regex": "6.26.0",
+        "babel-runtime": "6.26.0",
+        "regexpu-core": "2.0.0"
+      }
+    },
+    "babel-plugin-transform-regenerator": {
+      "version": "6.26.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-regenerator/-/babel-plugin-transform-regenerator-6.26.0.tgz",
+      "integrity": "sha1-4HA2lvveJ/Cj78rPi03KL3s6jy8=",
+      "dev": true,
+      "requires": {
+        "regenerator-transform": "0.10.1"
+      }
+    },
     "babel-plugin-transform-strict-mode": {
       "version": "6.24.1",
       "resolved": "https://registry.npmjs.org/babel-plugin-transform-strict-mode/-/babel-plugin-transform-strict-mode-6.24.1.tgz",
@@ -518,6 +807,38 @@
         "babel-types": "6.26.0"
       }
     },
+    "babel-preset-es2015": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-preset-es2015/-/babel-preset-es2015-6.24.1.tgz",
+      "integrity": "sha1-1EBQ1rwsn+6nAqrzjXJ6AhBTiTk=",
+      "dev": true,
+      "requires": {
+        "babel-plugin-check-es2015-constants": "6.22.0",
+        "babel-plugin-transform-es2015-arrow-functions": "6.22.0",
+        "babel-plugin-transform-es2015-block-scoped-functions": "6.22.0",
+        "babel-plugin-transform-es2015-block-scoping": "6.26.0",
+        "babel-plugin-transform-es2015-classes": "6.24.1",
+        "babel-plugin-transform-es2015-computed-properties": "6.24.1",
+        "babel-plugin-transform-es2015-destructuring": "6.23.0",
+        "babel-plugin-transform-es2015-duplicate-keys": "6.24.1",
+        "babel-plugin-transform-es2015-for-of": "6.23.0",
+        "babel-plugin-transform-es2015-function-name": "6.24.1",
+        "babel-plugin-transform-es2015-literals": "6.22.0",
+        "babel-plugin-transform-es2015-modules-amd": "6.24.1",
+        "babel-plugin-transform-es2015-modules-commonjs": "6.26.0",
+        "babel-plugin-transform-es2015-modules-systemjs": "6.24.1",
+        "babel-plugin-transform-es2015-modules-umd": "6.24.1",
+        "babel-plugin-transform-es2015-object-super": "6.24.1",
+        "babel-plugin-transform-es2015-parameters": "6.24.1",
+        "babel-plugin-transform-es2015-shorthand-properties": "6.24.1",
+        "babel-plugin-transform-es2015-spread": "6.22.0",
+        "babel-plugin-transform-es2015-sticky-regex": "6.24.1",
+        "babel-plugin-transform-es2015-template-literals": "6.22.0",
+        "babel-plugin-transform-es2015-typeof-symbol": "6.23.0",
+        "babel-plugin-transform-es2015-unicode-regex": "6.24.1",
+        "babel-plugin-transform-regenerator": "6.26.0"
+      }
+    },
     "babel-register": {
       "version": "6.26.0",
       "resolved": "https://registry.npmjs.org/babel-register/-/babel-register-6.26.0.tgz",
@@ -2242,15 +2563,6 @@
         "mime-types": "2.1.17"
       }
     },
-    "fs-access": {
-      "version": "1.0.1",
-      "resolved": "https://registry.npmjs.org/fs-access/-/fs-access-1.0.1.tgz",
-      "integrity": "sha1-1qh/JiJxzv6+wwxVNAf7mV2od3o=",
-      "dev": true,
-      "requires": {
-        "null-check": "1.0.0"
-      }
-    },
     "fs-extra": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/fs-extra/-/fs-extra-1.0.0.tgz",
@@ -4177,16 +4489,6 @@
       "integrity": "sha1-vuWtQEAFF4Ea40u5RfdikJEIt5o=",
       "dev": true
     },
-    "karma-chrome-launcher": {
-      "version": "2.2.0",
-      "resolved": "https://registry.npmjs.org/karma-chrome-launcher/-/karma-chrome-launcher-2.2.0.tgz",
-      "integrity": "sha512-uf/ZVpAabDBPvdPdveyk1EPgbnloPvFFGgmRhYLTDH7gEB4nZdSBk8yTU47w1g/drLSx5uMOkjKk7IWKfWg/+w==",
-      "dev": true,
-      "requires": {
-        "fs-access": "1.0.1",
-        "which": "1.3.0"
-      }
-    },
     "karma-mocha": {
       "version": "1.3.0",
       "resolved": "https://registry.npmjs.org/karma-mocha/-/karma-mocha-1.3.0.tgz",
@@ -4816,12 +5118,6 @@
         "remove-trailing-separator": "1.1.0"
       }
     },
-    "null-check": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/null-check/-/null-check-1.0.0.tgz",
-      "integrity": "sha1-l33/1xdgErnsMNKjnbXPcqBDnt0=",
-      "dev": true
-    },
     "number-is-nan": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/number-is-nan/-/number-is-nan-1.0.1.tgz",
@@ -5332,12 +5628,29 @@
         "set-immediate-shim": "1.0.1"
       }
     },
+    "regenerate": {
+      "version": "1.3.3",
+      "resolved": "https://registry.npmjs.org/regenerate/-/regenerate-1.3.3.tgz",
+      "integrity": "sha512-jVpo1GadrDAK59t/0jRx5VxYWQEDkkEKi6+HjE3joFVLfDOh9Xrdh0dF1eSq+BI/SwvTQ44gSscJ8N5zYL61sg==",
+      "dev": true
+    },
     "regenerator-runtime": {
       "version": "0.11.1",
       "resolved": "https://registry.npmjs.org/regenerator-runtime/-/regenerator-runtime-0.11.1.tgz",
       "integrity": "sha512-MguG95oij0fC3QV3URf4V2SDYGJhJnJGqvIIgdECeODCT98wSWDAJ94SSuVpYQUoTcGUIL6L4yNB7j1DFFHSBg==",
       "dev": true
     },
+    "regenerator-transform": {
+      "version": "0.10.1",
+      "resolved": "https://registry.npmjs.org/regenerator-transform/-/regenerator-transform-0.10.1.tgz",
+      "integrity": "sha512-PJepbvDbuK1xgIgnau7Y90cwaAmO/LCLMI2mPvaXq2heGMR3aWW5/BQvYrhJ8jgmQjXewXvBjzfqKcVOmhjZ6Q==",
+      "dev": true,
+      "requires": {
+        "babel-runtime": "6.26.0",
+        "babel-types": "6.26.0",
+        "private": "0.1.8"
+      }
+    },
     "regex-cache": {
       "version": "0.4.4",
       "resolved": "https://registry.npmjs.org/regex-cache/-/regex-cache-0.4.4.tgz",
@@ -5347,6 +5660,40 @@
         "is-equal-shallow": "0.1.3"
       }
     },
+    "regexpu-core": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/regexpu-core/-/regexpu-core-2.0.0.tgz",
+      "integrity": "sha1-SdA4g3uNz4v6W5pCE5k45uoq4kA=",
+      "dev": true,
+      "requires": {
+        "regenerate": "1.3.3",
+        "regjsgen": "0.2.0",
+        "regjsparser": "0.1.5"
+      }
+    },
+    "regjsgen": {
+      "version": "0.2.0",
+      "resolved": "https://registry.npmjs.org/regjsgen/-/regjsgen-0.2.0.tgz",
+      "integrity": "sha1-bAFq3qxVT3WCP+N6wFuS1aTtsfc=",
+      "dev": true
+    },
+    "regjsparser": {
+      "version": "0.1.5",
+      "resolved": "https://registry.npmjs.org/regjsparser/-/regjsparser-0.1.5.tgz",
+      "integrity": "sha1-fuj4Tcb6eS0/0K4ijSS9lJ6tIFw=",
+      "dev": true,
+      "requires": {
+        "jsesc": "0.5.0"
+      },
+      "dependencies": {
+        "jsesc": {
+          "version": "0.5.0",
+          "resolved": "https://registry.npmjs.org/jsesc/-/jsesc-0.5.0.tgz",
+          "integrity": "sha1-597mbjXW/Bb3EP6R1c9p9w8IkR0=",
+          "dev": true
+        }
+      }
+    },
     "remove-trailing-separator": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/remove-trailing-separator/-/remove-trailing-separator-1.1.0.tgz",
diff --git a/package.json b/package.json
index 215b537d..0c92e2aa 100644
--- a/package.json
+++ b/package.json
@@ -36,6 +36,7 @@
     "babel-plugin-transform-es2015-modules-commonjs": "^6.18.0",
     "babel-plugin-transform-es2015-modules-systemjs": "^6.22.0",
     "babel-plugin-transform-es2015-modules-umd": "^6.22.0",
+    "babel-preset-es2015": "^6.24.1",
     "babelify": "^7.3.0",
     "browserify": "^13.1.0",
     "chai": "^3.5.0",
diff --git a/utils/use_require.js b/utils/use_require.js
index b184a5d1..23b89362 100755
--- a/utils/use_require.js
+++ b/utils/use_require.js
@@ -90,6 +90,7 @@ var make_lib_files = function (import_format, source_maps, with_app_dir) {
 
     // NB: we need to make a copy of babel_opts, since babel sets some defaults on it
     const babel_opts = () => ({
+        presets: ['es2015'],
         plugins: [`transform-es2015-modules-${import_format}`],
         ast: false,
         sourceMaps: source_maps,