diff --git a/.babelrc b/.babelrc
index aef4ffa..383fd04 100644
--- a/.babelrc
+++ b/.babelrc
@@ -1,6 +1,6 @@
 {
   "presets": [
-    "es2015"
+    ["env", {"targts": {"node": "current"}}]
   ],
   "plugins": [
     "add-module-exports"
diff --git a/.travis.yml b/.travis.yml
index 225b3cf..29559a0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,7 +1,6 @@
 language: node_js
 node_js:
   - "6"
-  - "4"
 after_success:
   - npm run coveralls
 before_deploy:
diff --git a/package-lock.json b/package-lock.json
index c457edd..e7f994b 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -714,6 +714,17 @@
         "trim-right": "^1.0.1"
       }
     },
+    "babel-helper-builder-binary-assignment-operator-visitor": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-helper-builder-binary-assignment-operator-visitor/-/babel-helper-builder-binary-assignment-operator-visitor-6.24.1.tgz",
+      "integrity": "sha1-zORReto1b0IgvK6KAsKzRvmlZmQ=",
+      "dev": true,
+      "requires": {
+        "babel-helper-explode-assignable-expression": "^6.24.1",
+        "babel-runtime": "^6.22.0",
+        "babel-types": "^6.24.1"
+      }
+    },
     "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",
@@ -727,15 +738,56 @@
       }
     },
     "babel-helper-define-map": {
-      "version": "6.24.1",
-      "resolved": "https://registry.npmjs.org/babel-helper-define-map/-/babel-helper-define-map-6.24.1.tgz",
-      "integrity": "sha1-epdH8ljYlH0y1RX2qhx70CIEoIA=",
+      "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"
+      },
+      "dependencies": {
+        "babel-runtime": {
+          "version": "6.26.0",
+          "resolved": "https://registry.npmjs.org/babel-runtime/-/babel-runtime-6.26.0.tgz",
+          "integrity": "sha1-llxwWGaOgrVde/4E/yM3vItWR/4=",
+          "dev": true,
+          "requires": {
+            "core-js": "^2.4.0",
+            "regenerator-runtime": "^0.11.0"
+          }
+        },
+        "babel-types": {
+          "version": "6.26.0",
+          "resolved": "https://registry.npmjs.org/babel-types/-/babel-types-6.26.0.tgz",
+          "integrity": "sha1-o7Bz+Uq0nrb6Vc1lInozQ4BjJJc=",
+          "dev": true,
+          "requires": {
+            "babel-runtime": "^6.26.0",
+            "esutils": "^2.0.2",
+            "lodash": "^4.17.4",
+            "to-fast-properties": "^1.0.3"
+          }
+        },
+        "regenerator-runtime": {
+          "version": "0.11.1",
+          "resolved": "https://registry.npmjs.org/regenerator-runtime/-/regenerator-runtime-0.11.1.tgz",
+          "integrity": "sha512-MguG95oij0fC3QV3URf4V2SDYGJhJnJGqvIIgdECeODCT98wSWDAJ94SSuVpYQUoTcGUIL6L4yNB7j1DFFHSBg==",
+          "dev": true
+        }
+      }
+    },
+    "babel-helper-explode-assignable-expression": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-helper-explode-assignable-expression/-/babel-helper-explode-assignable-expression-6.24.1.tgz",
+      "integrity": "sha1-8luCz33BBDPFX3BZLVdGQArCLKo=",
+      "dev": true,
+      "requires": {
         "babel-runtime": "^6.22.0",
-        "babel-types": "^6.24.1",
-        "lodash": "^4.2.0"
+        "babel-traverse": "^6.24.1",
+        "babel-types": "^6.24.1"
       }
     },
     "babel-helper-function-name": {
@@ -782,14 +834,57 @@
       }
     },
     "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"
+      },
+      "dependencies": {
+        "babel-runtime": {
+          "version": "6.26.0",
+          "resolved": "https://registry.npmjs.org/babel-runtime/-/babel-runtime-6.26.0.tgz",
+          "integrity": "sha1-llxwWGaOgrVde/4E/yM3vItWR/4=",
+          "dev": true,
+          "requires": {
+            "core-js": "^2.4.0",
+            "regenerator-runtime": "^0.11.0"
+          }
+        },
+        "babel-types": {
+          "version": "6.26.0",
+          "resolved": "https://registry.npmjs.org/babel-types/-/babel-types-6.26.0.tgz",
+          "integrity": "sha1-o7Bz+Uq0nrb6Vc1lInozQ4BjJJc=",
+          "dev": true,
+          "requires": {
+            "babel-runtime": "^6.26.0",
+            "esutils": "^2.0.2",
+            "lodash": "^4.17.4",
+            "to-fast-properties": "^1.0.3"
+          }
+        },
+        "regenerator-runtime": {
+          "version": "0.11.1",
+          "resolved": "https://registry.npmjs.org/regenerator-runtime/-/regenerator-runtime-0.11.1.tgz",
+          "integrity": "sha512-MguG95oij0fC3QV3URf4V2SDYGJhJnJGqvIIgdECeODCT98wSWDAJ94SSuVpYQUoTcGUIL6L4yNB7j1DFFHSBg==",
+          "dev": true
+        }
+      }
+    },
+    "babel-helper-remap-async-to-generator": {
       "version": "6.24.1",
-      "resolved": "https://registry.npmjs.org/babel-helper-regex/-/babel-helper-regex-6.24.1.tgz",
-      "integrity": "sha1-024i+rEAjXnYhkjjIRaGgShFbOg=",
+      "resolved": "https://registry.npmjs.org/babel-helper-remap-async-to-generator/-/babel-helper-remap-async-to-generator-6.24.1.tgz",
+      "integrity": "sha1-XsWBgnrXI/7N04HxySg5BnbkVRs=",
       "dev": true,
       "requires": {
+        "babel-helper-function-name": "^6.24.1",
         "babel-runtime": "^6.22.0",
-        "babel-types": "^6.24.1",
-        "lodash": "^4.2.0"
+        "babel-template": "^6.24.1",
+        "babel-traverse": "^6.24.1",
+        "babel-types": "^6.24.1"
       }
     },
     "babel-helper-replace-supers": {
@@ -1218,6 +1313,35 @@
         "babel-runtime": "^6.22.0"
       }
     },
+    "babel-plugin-syntax-async-functions": {
+      "version": "6.13.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-syntax-async-functions/-/babel-plugin-syntax-async-functions-6.13.0.tgz",
+      "integrity": "sha1-ytnK0RkbWtY0vzCuCHI5HgZHvpU=",
+      "dev": true
+    },
+    "babel-plugin-syntax-exponentiation-operator": {
+      "version": "6.13.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-syntax-exponentiation-operator/-/babel-plugin-syntax-exponentiation-operator-6.13.0.tgz",
+      "integrity": "sha1-nufoM3KQ2pUoggGmpX9BcDF4MN4=",
+      "dev": true
+    },
+    "babel-plugin-syntax-trailing-function-commas": {
+      "version": "6.22.0",
+      "resolved": "https://registry.npmjs.org/babel-plugin-syntax-trailing-function-commas/-/babel-plugin-syntax-trailing-function-commas-6.22.0.tgz",
+      "integrity": "sha1-ugNgk3+NBuQBgKQ/4NVhb/9TLPM=",
+      "dev": true
+    },
+    "babel-plugin-transform-async-to-generator": {
+      "version": "6.24.1",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-async-to-generator/-/babel-plugin-transform-async-to-generator-6.24.1.tgz",
+      "integrity": "sha1-ZTbjeK/2yx1VF6wOQOs+n8jQh2E=",
+      "dev": true,
+      "requires": {
+        "babel-helper-remap-async-to-generator": "^6.24.1",
+        "babel-plugin-syntax-async-functions": "^6.8.0",
+        "babel-runtime": "^6.22.0"
+      }
+    },
     "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",
@@ -1237,16 +1361,93 @@
       }
     },
     "babel-plugin-transform-es2015-block-scoping": {
-      "version": "6.24.1",
-      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-block-scoping/-/babel-plugin-transform-es2015-block-scoping-6.24.1.tgz",
-      "integrity": "sha1-dsKV3DpHQbFmWt/TFnIV3P8ypXY=",
+      "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": "^6.22.0",
-        "babel-template": "^6.24.1",
-        "babel-traverse": "^6.24.1",
-        "babel-types": "^6.24.1",
-        "lodash": "^4.2.0"
+        "babel-runtime": "^6.26.0",
+        "babel-template": "^6.26.0",
+        "babel-traverse": "^6.26.0",
+        "babel-types": "^6.26.0",
+        "lodash": "^4.17.4"
+      },
+      "dependencies": {
+        "babel-code-frame": {
+          "version": "6.26.0",
+          "resolved": "https://registry.npmjs.org/babel-code-frame/-/babel-code-frame-6.26.0.tgz",
+          "integrity": "sha1-Y/1D99weO7fONZR9uP42mj9Yx0s=",
+          "dev": true,
+          "requires": {
+            "chalk": "^1.1.3",
+            "esutils": "^2.0.2",
+            "js-tokens": "^3.0.2"
+          }
+        },
+        "babel-runtime": {
+          "version": "6.26.0",
+          "resolved": "https://registry.npmjs.org/babel-runtime/-/babel-runtime-6.26.0.tgz",
+          "integrity": "sha1-llxwWGaOgrVde/4E/yM3vItWR/4=",
+          "dev": true,
+          "requires": {
+            "core-js": "^2.4.0",
+            "regenerator-runtime": "^0.11.0"
+          }
+        },
+        "babel-template": {
+          "version": "6.26.0",
+          "resolved": "https://registry.npmjs.org/babel-template/-/babel-template-6.26.0.tgz",
+          "integrity": "sha1-3gPi0WOWsGn0bdn/+FIfsaDjXgI=",
+          "dev": true,
+          "requires": {
+            "babel-runtime": "^6.26.0",
+            "babel-traverse": "^6.26.0",
+            "babel-types": "^6.26.0",
+            "babylon": "^6.18.0",
+            "lodash": "^4.17.4"
+          }
+        },
+        "babel-traverse": {
+          "version": "6.26.0",
+          "resolved": "https://registry.npmjs.org/babel-traverse/-/babel-traverse-6.26.0.tgz",
+          "integrity": "sha1-RqnL1+3MYsjlwGTi0tjQ9ANXZu4=",
+          "dev": true,
+          "requires": {
+            "babel-code-frame": "^6.26.0",
+            "babel-messages": "^6.23.0",
+            "babel-runtime": "^6.26.0",
+            "babel-types": "^6.26.0",
+            "babylon": "^6.18.0",
+            "debug": "^2.6.8",
+            "globals": "^9.18.0",
+            "invariant": "^2.2.2",
+            "lodash": "^4.17.4"
+          }
+        },
+        "babel-types": {
+          "version": "6.26.0",
+          "resolved": "https://registry.npmjs.org/babel-types/-/babel-types-6.26.0.tgz",
+          "integrity": "sha1-o7Bz+Uq0nrb6Vc1lInozQ4BjJJc=",
+          "dev": true,
+          "requires": {
+            "babel-runtime": "^6.26.0",
+            "esutils": "^2.0.2",
+            "lodash": "^4.17.4",
+            "to-fast-properties": "^1.0.3"
+          }
+        },
+        "babylon": {
+          "version": "6.18.0",
+          "resolved": "https://registry.npmjs.org/babylon/-/babylon-6.18.0.tgz",
+          "integrity": "sha512-q/UEjfGJ2Cm3oKV71DJz9d25TPnq5rhBVL2Q4fA5wcC3jcrdn7+SssEybFIxwAvvP+YCsCYNKughoF33GxgycQ==",
+          "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
+        }
       }
     },
     "babel-plugin-transform-es2015-classes": {
@@ -1336,15 +1537,92 @@
       }
     },
     "babel-plugin-transform-es2015-modules-commonjs": {
-      "version": "6.24.1",
-      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-modules-commonjs/-/babel-plugin-transform-es2015-modules-commonjs-6.24.1.tgz",
-      "integrity": "sha1-0+MQtA72ZKNmIiAAl8bUQCmPK/4=",
+      "version": "6.26.2",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-es2015-modules-commonjs/-/babel-plugin-transform-es2015-modules-commonjs-6.26.2.tgz",
+      "integrity": "sha512-CV9ROOHEdrjcwhIaJNBGMBCodN+1cfkwtM1SbUHmvyy35KGT7fohbpOxkE2uLz1o6odKK2Ck/tz47z+VqQfi9Q==",
       "dev": true,
       "requires": {
         "babel-plugin-transform-strict-mode": "^6.24.1",
-        "babel-runtime": "^6.22.0",
-        "babel-template": "^6.24.1",
-        "babel-types": "^6.24.1"
+        "babel-runtime": "^6.26.0",
+        "babel-template": "^6.26.0",
+        "babel-types": "^6.26.0"
+      },
+      "dependencies": {
+        "babel-code-frame": {
+          "version": "6.26.0",
+          "resolved": "https://registry.npmjs.org/babel-code-frame/-/babel-code-frame-6.26.0.tgz",
+          "integrity": "sha1-Y/1D99weO7fONZR9uP42mj9Yx0s=",
+          "dev": true,
+          "requires": {
+            "chalk": "^1.1.3",
+            "esutils": "^2.0.2",
+            "js-tokens": "^3.0.2"
+          }
+        },
+        "babel-runtime": {
+          "version": "6.26.0",
+          "resolved": "https://registry.npmjs.org/babel-runtime/-/babel-runtime-6.26.0.tgz",
+          "integrity": "sha1-llxwWGaOgrVde/4E/yM3vItWR/4=",
+          "dev": true,
+          "requires": {
+            "core-js": "^2.4.0",
+            "regenerator-runtime": "^0.11.0"
+          }
+        },
+        "babel-template": {
+          "version": "6.26.0",
+          "resolved": "https://registry.npmjs.org/babel-template/-/babel-template-6.26.0.tgz",
+          "integrity": "sha1-3gPi0WOWsGn0bdn/+FIfsaDjXgI=",
+          "dev": true,
+          "requires": {
+            "babel-runtime": "^6.26.0",
+            "babel-traverse": "^6.26.0",
+            "babel-types": "^6.26.0",
+            "babylon": "^6.18.0",
+            "lodash": "^4.17.4"
+          }
+        },
+        "babel-traverse": {
+          "version": "6.26.0",
+          "resolved": "https://registry.npmjs.org/babel-traverse/-/babel-traverse-6.26.0.tgz",
+          "integrity": "sha1-RqnL1+3MYsjlwGTi0tjQ9ANXZu4=",
+          "dev": true,
+          "requires": {
+            "babel-code-frame": "^6.26.0",
+            "babel-messages": "^6.23.0",
+            "babel-runtime": "^6.26.0",
+            "babel-types": "^6.26.0",
+            "babylon": "^6.18.0",
+            "debug": "^2.6.8",
+            "globals": "^9.18.0",
+            "invariant": "^2.2.2",
+            "lodash": "^4.17.4"
+          }
+        },
+        "babel-types": {
+          "version": "6.26.0",
+          "resolved": "https://registry.npmjs.org/babel-types/-/babel-types-6.26.0.tgz",
+          "integrity": "sha1-o7Bz+Uq0nrb6Vc1lInozQ4BjJJc=",
+          "dev": true,
+          "requires": {
+            "babel-runtime": "^6.26.0",
+            "esutils": "^2.0.2",
+            "lodash": "^4.17.4",
+            "to-fast-properties": "^1.0.3"
+          }
+        },
+        "babylon": {
+          "version": "6.18.0",
+          "resolved": "https://registry.npmjs.org/babylon/-/babylon-6.18.0.tgz",
+          "integrity": "sha512-q/UEjfGJ2Cm3oKV71DJz9d25TPnq5rhBVL2Q4fA5wcC3jcrdn7+SssEybFIxwAvvP+YCsCYNKughoF33GxgycQ==",
+          "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
+        }
       }
     },
     "babel-plugin-transform-es2015-modules-systemjs": {
@@ -1452,13 +1730,24 @@
         "regexpu-core": "^2.0.0"
       }
     },
-    "babel-plugin-transform-regenerator": {
+    "babel-plugin-transform-exponentiation-operator": {
       "version": "6.24.1",
-      "resolved": "https://registry.npmjs.org/babel-plugin-transform-regenerator/-/babel-plugin-transform-regenerator-6.24.1.tgz",
-      "integrity": "sha1-uNowWtQ8PJm0hI5P5AN7dw0jxBg=",
+      "resolved": "https://registry.npmjs.org/babel-plugin-transform-exponentiation-operator/-/babel-plugin-transform-exponentiation-operator-6.24.1.tgz",
+      "integrity": "sha1-KrDJx/MJj6SJB3cruBP+QejeOg4=",
       "dev": true,
       "requires": {
-        "regenerator-transform": "0.9.11"
+        "babel-helper-builder-binary-assignment-operator-visitor": "^6.24.1",
+        "babel-plugin-syntax-exponentiation-operator": "^6.8.0",
+        "babel-runtime": "^6.22.0"
+      }
+    },
+    "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": "^0.10.0"
       }
     },
     "babel-plugin-transform-strict-mode": {
@@ -1508,36 +1797,42 @@
         }
       }
     },
-    "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=",
+    "babel-preset-env": {
+      "version": "1.7.0",
+      "resolved": "https://registry.npmjs.org/babel-preset-env/-/babel-preset-env-1.7.0.tgz",
+      "integrity": "sha512-9OR2afuKDneX2/q2EurSftUYM0xGu4O2D9adAhVfADDhrYDaxXV0rBbevVYoY9n6nyX1PmQW/0jtpJvUNr9CHg==",
       "dev": true,
       "requires": {
         "babel-plugin-check-es2015-constants": "^6.22.0",
+        "babel-plugin-syntax-trailing-function-commas": "^6.22.0",
+        "babel-plugin-transform-async-to-generator": "^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": "^6.24.1",
-        "babel-plugin-transform-es2015-classes": "^6.24.1",
-        "babel-plugin-transform-es2015-computed-properties": "^6.24.1",
-        "babel-plugin-transform-es2015-destructuring": "^6.22.0",
-        "babel-plugin-transform-es2015-duplicate-keys": "^6.24.1",
-        "babel-plugin-transform-es2015-for-of": "^6.22.0",
-        "babel-plugin-transform-es2015-function-name": "^6.24.1",
+        "babel-plugin-transform-es2015-block-scoping": "^6.23.0",
+        "babel-plugin-transform-es2015-classes": "^6.23.0",
+        "babel-plugin-transform-es2015-computed-properties": "^6.22.0",
+        "babel-plugin-transform-es2015-destructuring": "^6.23.0",
+        "babel-plugin-transform-es2015-duplicate-keys": "^6.22.0",
+        "babel-plugin-transform-es2015-for-of": "^6.23.0",
+        "babel-plugin-transform-es2015-function-name": "^6.22.0",
         "babel-plugin-transform-es2015-literals": "^6.22.0",
-        "babel-plugin-transform-es2015-modules-amd": "^6.24.1",
-        "babel-plugin-transform-es2015-modules-commonjs": "^6.24.1",
-        "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-modules-amd": "^6.22.0",
+        "babel-plugin-transform-es2015-modules-commonjs": "^6.23.0",
+        "babel-plugin-transform-es2015-modules-systemjs": "^6.23.0",
+        "babel-plugin-transform-es2015-modules-umd": "^6.23.0",
+        "babel-plugin-transform-es2015-object-super": "^6.22.0",
+        "babel-plugin-transform-es2015-parameters": "^6.23.0",
+        "babel-plugin-transform-es2015-shorthand-properties": "^6.22.0",
         "babel-plugin-transform-es2015-spread": "^6.22.0",
-        "babel-plugin-transform-es2015-sticky-regex": "^6.24.1",
+        "babel-plugin-transform-es2015-sticky-regex": "^6.22.0",
         "babel-plugin-transform-es2015-template-literals": "^6.22.0",
-        "babel-plugin-transform-es2015-typeof-symbol": "^6.22.0",
-        "babel-plugin-transform-es2015-unicode-regex": "^6.24.1",
-        "babel-plugin-transform-regenerator": "^6.24.1"
+        "babel-plugin-transform-es2015-typeof-symbol": "^6.23.0",
+        "babel-plugin-transform-es2015-unicode-regex": "^6.22.0",
+        "babel-plugin-transform-exponentiation-operator": "^6.22.0",
+        "babel-plugin-transform-regenerator": "^6.22.0",
+        "browserslist": "^3.2.6",
+        "invariant": "^2.2.2",
+        "semver": "^5.3.0"
       }
     },
     "babel-register": {
@@ -1853,6 +2148,16 @@
         "pako": "~1.0.5"
       }
     },
+    "browserslist": {
+      "version": "3.2.8",
+      "resolved": "https://registry.npmjs.org/browserslist/-/browserslist-3.2.8.tgz",
+      "integrity": "sha512-WHVocJYavUwVgVViC0ORikPHQquXwVh939TaelZ4WDqpWgTX/FsGhl/+P4qBUAGcRvtOgDgC+xftNWWp2RUTAQ==",
+      "dev": true,
+      "requires": {
+        "caniuse-lite": "^1.0.30000844",
+        "electron-to-chromium": "^1.3.47"
+      }
+    },
     "buffer": {
       "version": "4.9.1",
       "resolved": "https://registry.npmjs.org/buffer/-/buffer-4.9.1.tgz",
@@ -1973,6 +2278,12 @@
       "dev": true,
       "optional": true
     },
+    "caniuse-lite": {
+      "version": "1.0.30000930",
+      "resolved": "https://registry.npmjs.org/caniuse-lite/-/caniuse-lite-1.0.30000930.tgz",
+      "integrity": "sha512-KD+pw9DderBLB8CGqBzYyFWpnrPVOEjsjargU/CvkNyg60od3cxSPTcTeMPhxJhDbkQPWvOz5BAyBzNl/St9vg==",
+      "dev": true
+    },
     "caseless": {
       "version": "0.12.0",
       "resolved": "https://registry.npmjs.org/caseless/-/caseless-0.12.0.tgz",
@@ -2143,12 +2454,6 @@
         }
       }
     },
-    "coffee-script": {
-      "version": "1.12.7",
-      "resolved": "https://registry.npmjs.org/coffee-script/-/coffee-script-1.12.7.tgz",
-      "integrity": "sha512-fLeEhqwymYat/MpTPUjSKHVYYl0ec2mOyALEMLmzr5i1isuG+6jfI2j2d5oBO3VIzgUXgBVIcOT9uH1TFxBckw==",
-      "dev": true
-    },
     "coffeelint": {
       "version": "2.1.0",
       "resolved": "https://registry.npmjs.org/coffeelint/-/coffeelint-2.1.0.tgz",
@@ -2171,6 +2476,12 @@
         }
       }
     },
+    "coffeescript": {
+      "version": "2.3.2",
+      "resolved": "https://registry.npmjs.org/coffeescript/-/coffeescript-2.3.2.tgz",
+      "integrity": "sha512-YObiFDoukx7qPBi/K0kUKyntEZDfBQiqs/DbrR1xzASKOBjGT7auD85/DiPeRr9k++lRj7l3uA9TNMLfyfcD/Q==",
+      "dev": true
+    },
     "collection-visit": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/collection-visit/-/collection-visit-1.0.0.tgz",
@@ -2617,6 +2928,12 @@
       "integrity": "sha512-0xy4A/twfrRCnkhfk8ErDi5DqdAsAqeGxht4xkCUrsvhhbQNs7E+4jV0CN7+NKIY0aHE72+XvqtBIXzD31ZbXQ==",
       "dev": true
     },
+    "electron-to-chromium": {
+      "version": "1.3.106",
+      "resolved": "https://registry.npmjs.org/electron-to-chromium/-/electron-to-chromium-1.3.106.tgz",
+      "integrity": "sha512-eXX45p4q9CRxG0G8D3ZBZYSdN3DnrcZfrFvt6VUr1u7aKITEtRY/xwWzJ/UZcWXa7DMqPu/pYwuZ6Nm+bl0GmA==",
+      "dev": true
+    },
     "elliptic": {
       "version": "6.4.1",
       "resolved": "https://registry.npmjs.org/elliptic/-/elliptic-6.4.1.tgz",
@@ -5404,9 +5721,9 @@
       "optional": true
     },
     "private": {
-      "version": "0.1.7",
-      "resolved": "https://registry.npmjs.org/private/-/private-0.1.7.tgz",
-      "integrity": "sha1-aM5eih7woju1cMwoU3tTMqumPvE=",
+      "version": "0.1.8",
+      "resolved": "https://registry.npmjs.org/private/-/private-0.1.8.tgz",
+      "integrity": "sha512-VvivMrbvd2nKkiG38qjULzlc+4Vx4wm/whI9pQD35YrARNnhxeiRktSOhSukRLFNlzg6Br/cJPet5J/u19r/mg==",
       "dev": true
     },
     "process": {
@@ -5866,9 +6183,9 @@
       }
     },
     "regenerate": {
-      "version": "1.3.2",
-      "resolved": "https://registry.npmjs.org/regenerate/-/regenerate-1.3.2.tgz",
-      "integrity": "sha1-0ZQcZ7rUN+G+dkM63Vs4X5WxkmA=",
+      "version": "1.4.0",
+      "resolved": "https://registry.npmjs.org/regenerate/-/regenerate-1.4.0.tgz",
+      "integrity": "sha512-1G6jJVDWrt0rK99kBjvEtziZNCICAuvIPkSiUFIQxVP06RCVpq3dmDo2oi6ABpYaDYaTRr67BEhL8r1wgEZZKg==",
       "dev": true
     },
     "regenerator-runtime": {
@@ -5878,9 +6195,9 @@
       "dev": true
     },
     "regenerator-transform": {
-      "version": "0.9.11",
-      "resolved": "https://registry.npmjs.org/regenerator-transform/-/regenerator-transform-0.9.11.tgz",
-      "integrity": "sha1-On0GdSDLe3F2dp61/4aGkb7+EoM=",
+      "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": "^6.18.0",
diff --git a/package.json b/package.json
index 3560847..534055b 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "ejs-html-loader",
   "version": "3.1.0",
-  "description": "Webpack 2 loader for rendering HTML from EJS templates",
+  "description": "Webpack loader for rendering HTML from EJS templates",
   "main": "lib/index.js",
   "scripts": {
     "build": "npm run unbuild && babel src -d lib",
@@ -13,7 +13,7 @@
     "coveralls": "cat coverage/lcov.info | coveralls"
   },
   "engines": {
-    "node": ">=4"
+    "node": ">=6"
   },
   "repository": {
     "type": "git",
@@ -27,7 +27,7 @@
     "html",
     "template"
   ],
-  "author": "Akim McMath <akim.elijah.mcmath@gmail.com>",
+  "author": "Akim McMath <akim@mcmath.io> (http://www.mcmath.io/)",
   "license": "MIT",
   "bugs": {
     "url": "https://github.com/mcmath/ejs-html-loader/issues"
@@ -44,11 +44,11 @@
     "@mcmath/coffeelint-config": "^1.0.1",
     "babel-cli": "^6.26.0",
     "babel-plugin-add-module-exports": "^1.0.0",
-    "babel-preset-es2015": "^6.24.1",
+    "babel-preset-env": "^1.7.0",
     "babel-register": "^6.26.0",
     "chai": "^4.2.0",
-    "coffee-script": "^1.12.5",
     "coffeelint": "^2.1.0",
+    "coffeescript": "^2.3.2",
     "coveralls": "^3.0.2",
     "ejs": "^2.6.1",
     "eslint": "^5.12.1",
diff --git a/test/mocha.opts b/test/mocha.opts
index 46a7640..d215465 100644
--- a/test/mocha.opts
+++ b/test/mocha.opts
@@ -1,4 +1,4 @@
 --recursive
 --reporter spec
 --require babel-core/register
---require coffee-script/register
+--require coffeescript/register