diff --git a/.babelrc b/.babelrc
index c1dec08..a5a06b4 100644
--- a/.babelrc
+++ b/.babelrc
@@ -3,14 +3,18 @@
         [
             "env",
             {
+                "useBuiltIns": "entry",
                 "modules": false,
                 "targets": {
                     "browsers": [
-                        "last 2 Chrome versions"
+                        "> 0.5%",
+                        "last 2 versions",
+                        "Firefox ESR",
+                        "not dead"
                     ]
                 }
             }
         ],
         "stage-2"
-    ]
+    ],
 }
\ No newline at end of file
diff --git a/package.json b/package.json
index 66ae5c2..dd78813 100644
--- a/package.json
+++ b/package.json
@@ -33,6 +33,7 @@
   },
   "dependencies": {
     "@octokit/rest": "^15.6.2",
+    "babel-polyfill": "^6.26.0",
     "bottleneck": "^2.3.1",
     "octonode": "^0.9.2"
   },
diff --git a/src/index.ts b/src/index.ts
index b9ed9bb..20e5a8e 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,10 +1,11 @@
+import 'babel-polyfill';
 import { Greeter } from './greeter';
 // tslint:disable-next-line:ordered-imports
 import { fetchUnusedForkedRepos, runMain } from './gh';
 export * from './greeter';
 
 // tslint:disable-next-line:only-arrow-functions
-(function (currentWindow: Window) {
+(function(currentWindow: Window) {
   // execute when load index.js
 
   // tslint:disable-next-line:no-console
diff --git a/yarn.lock b/yarn.lock
index 66c9058..e52f7d0 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -792,6 +792,14 @@ babel-plugin-transform-strict-mode@^6.24.1:
     babel-runtime "^6.22.0"
     babel-types "^6.24.1"
 
+babel-polyfill@^6.26.0:
+  version "6.26.0"
+  resolved "https://registry.yarnpkg.com/babel-polyfill/-/babel-polyfill-6.26.0.tgz#379937abc67d7895970adc621f284cd966cf2153"
+  dependencies:
+    babel-runtime "^6.26.0"
+    core-js "^2.5.0"
+    regenerator-runtime "^0.10.5"
+
 babel-preset-env@^1.6.1:
   version "1.7.0"
   resolved "https://registry.yarnpkg.com/babel-preset-env/-/babel-preset-env-1.7.0.tgz#dea79fa4ebeb883cd35dab07e260c1c9c04df77a"
@@ -4660,6 +4668,10 @@ regenerate@^1.2.1:
   version "1.4.0"
   resolved "https://registry.yarnpkg.com/regenerate/-/regenerate-1.4.0.tgz#4a856ec4b56e4077c557589cae85e7a4c8869a11"
 
+regenerator-runtime@^0.10.5:
+  version "0.10.5"
+  resolved "https://registry.yarnpkg.com/regenerator-runtime/-/regenerator-runtime-0.10.5.tgz#336c3efc1220adcedda2c9fab67b5a7955a33658"
+
 regenerator-runtime@^0.11.0:
   version "0.11.1"
   resolved "https://registry.yarnpkg.com/regenerator-runtime/-/regenerator-runtime-0.11.1.tgz#be05ad7f9bf7d22e056f9726cee5017fbf19e2e9"