Fix for FormData being null in node

Author: zackify

package.json

@@ -1,6 +1,6 @@
 {
   "name": "legible",
-  "version": "0.2.10",
+  "version": "0.2.11",
   "description": "cleanly code your api requests",
   "main": "dist/index.js",
   "scripts": {

src/utilities/body.js

@@ -2,7 +2,7 @@ export default (body) => {
   // Handle empty case
   if (!body) return null
   // Handle FormData
-  if (body instanceof FormData) return body
+  if (typeof FormData !== 'undefined' && body instanceof FormData) return body
   try {
     // Handle already stringified JSON
     JSON.parse(body)