diff --git a/.babelrc b/.babelrc
new file mode 100644
index 0000000..8bf96f5
--- /dev/null
+++ b/.babelrc
@@ -0,0 +1,9 @@
+{
+  "presets": [
+    ["env", {
+        "targets": {
+            "node": "4"
+        }
+    }]
+  ]
+}
diff --git a/.eslintignore b/.eslintignore
index de153db..ca34586 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -1 +1,2 @@
-artifacts
+/artifacts
+/semver-intersect.js
diff --git a/.gitignore b/.gitignore
index 1ec7489..22636fb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,4 @@
 .nyc_output
 artifacts
 node_modules
+semver-intersect.js
diff --git a/.npmignore b/.npmignore
index 2a5fcec..1de7a02 100644
--- a/.npmignore
+++ b/.npmignore
@@ -6,4 +6,5 @@
 .nyc_output
 .travis.yml
 artifacts
+src
 tests
diff --git a/.travis.yml b/.travis.yml
index 41480cd..c5eba4b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,3 +1,6 @@
 language: node_js
 node_js:
-  "node"
+  - 4
+  - 6
+  - 8
+  - 9
diff --git a/README.md b/README.md
index 4b05e34..b1e73e5 100644
--- a/README.md
+++ b/README.md
@@ -5,13 +5,13 @@ Get the intersection of multiple semver ranges
 const { intersect } = require('semver-intersect');
 
 // ^4.1.0
-intersect('^4.0.0', '^4.1.0');                        
+intersect('^4.0.0', '^4.1.0');
 
 // ~4.3.0
-intersect('^4.0.0', '~4.3.0');                        
+intersect('^4.0.0', '~4.3.0');
 
 // ~4.3.89
-intersect('^4.0.0', '~4.3.89', '~4.3.24', '~4.3.63'); 
+intersect('^4.0.0', '~4.3.89', '~4.3.24', '~4.3.63');
 
 // throws "Range >=4.5.0 is not compatible with <4.4.0"
 intersect('^4.0.0', '~4.3.0', '^4.5.0')
diff --git a/package.json b/package.json
index 2e86abd..1c68609 100644
--- a/package.json
+++ b/package.json
@@ -7,6 +7,9 @@
     },
     "description": "Get the intersection of multiple semver ranges",
     "devDependencies": {
+        "babel-cli": "^6.26.0",
+        "babel-preset-env": "^1.6.1",
+        "babel-register": "^6.26.0",
         "chai": "^4.0.0",
         "eslint": "^4.0.0",
         "jenkins-mocha": "^4.0.0"
@@ -22,8 +25,11 @@
         "url": "git@github.com:snyamathi/semver-intersect.git"
     },
     "scripts": {
+        "build": "babel src -d .",
         "lint": "eslint .",
-        "test": "jenkins-mocha tests/unit --recursive"
+        "prepublish": "npm run build",
+        "pretest": "npm run build",
+        "test": "jenkins-mocha tests/unit --recursive --compilers js:babel-register"
     },
     "version": "1.1.2"
 }
diff --git a/semver-intersect.js b/src/semver-intersect.js
similarity index 98%
rename from semver-intersect.js
rename to src/semver-intersect.js
index a0868d9..12f09fa 100644
--- a/semver-intersect.js
+++ b/src/semver-intersect.js
@@ -132,7 +132,7 @@ function parseRange (range) {
 
 function union (a, b) {
     return b.reduce((result, value) => {
-        if (!result.includes(value)) {
+        if (result.indexOf(value) === -1) {
             result.push(value);
         }
         return result;
diff --git a/tests/unit/semver-intersect.js b/tests/unit/semver-intersect.js
index 5195982..e791c0f 100644
--- a/tests/unit/semver-intersect.js
+++ b/tests/unit/semver-intersect.js
@@ -1,5 +1,4 @@
 const expect = require('chai').expect;
-const semver = require('semver');
 const {
     createShorthand,
     ensureCompatible,