Use includes instead of has

Author: gyx1000

src/http/_res-fmt.js

@@ -2,8 +2,6 @@ let httpError = require('./errors')
 let binaryTypes = require('./helpers/binary-types')
 let { brotliCompressSync } = require('zlib')
 
-let binaryTypesSet = new Set(binaryTypes)
-
 module.exports = function responseFormatter (req, params) {
   let isError = params instanceof Error
 
@@ -170,7 +168,7 @@ module.exports = function responseFormatter (req, params) {
 
   // Handle body encoding (if necessary)
   let [ cTest ] = (res.headers['content-type'] || '').split(';')
-  let isBinary = binaryTypesSet.has(cTest)
+  let isBinary = binaryTypes.includes(cTest)
   let bodyIsString = typeof res.body === 'string'
   let b64enc = i => new Buffer.from(i).toString('base64')
   function compress (body) {