set target for node 4

Author: beefancohen

.babelrc

@@ -1,4 +1,13 @@
 {
-  "presets": ["airbnb"],
+  "presets": [
+    [
+      "airbnb",
+      {
+        "targets": {
+          "node": 4
+        }
+      }
+    ]
+  ],
   "plugins": ["@babel/plugin-transform-flow-strip-types"]
 }