feat(response): added support to Uint8Array (#540)

Thanks again @H4ad! And thank you @Poitrin for the review and feedback

Author: H4ad

__tests__/integration.js

@@ -9,7 +9,6 @@ const {
   makeResponse,
   EACH_MATRIX
 } = require('../jest-helpers')
-
 const jestHelpersPath = path.join(__dirname, '..', 'jest-helpers')
 
 let app, router, serverlessExpressInstance

src/response.js

@@ -12,13 +12,15 @@ function getString (data) {
     return data.toString('utf8')
   } else if (typeof data === 'string') {
     return data
+  } else if (data instanceof Uint8Array) {
+    return new TextDecoder().decode(data)
   } else {
     throw new Error(`response.write() of unexpected type: ${typeof data}`)
   }
 }
 
 function addData (stream, data) {
-  if (Buffer.isBuffer(data) || typeof data === 'string') {
+  if (Buffer.isBuffer(data) || typeof data === 'string' || data instanceof Uint8Array) {
     stream[BODY].push(Buffer.from(data))
   } else {
     throw new Error(`response.write() of unexpected type: ${typeof data}`)