Adjusting the readableObjectMode test for earlier versions of Node

Author: aelnaiem

test/base.js

@@ -1,6 +1,7 @@
 'use strict'
 
 const http = require('http')
+const util = require('util')
 const split = require('split2')
 const test = require('tap').test
 const Fastify = require('fastify')
@@ -317,11 +318,16 @@ test('Should be able to pass custom connectionOptions to createWebSocketStream',
   fastify.register(fastifyWebsocket, { connectionOptions })
 
   fastify.get('/', { websocket: true }, (connection, request) => {
-    t.equal(connection.readableObjectMode, true)
+    // readableObjectMode was added in Node v12.3.0 so for earlier versions
+    // we check the encapsulated readable state directly
+    const mode = (typeof connection.readableObjectMode === 'undefined')
+      ? connection._readableState.objectMode
+      : connection.readableObjectMode
+    t.equal(mode, true)
     connection.socket.binaryType = 'arraybuffer'
 
     connection.once('data', (chunk) => {
-      const message = new TextDecoder().decode(chunk)
+      const message = new util.TextDecoder().decode(chunk)
       t.equal(message, 'Hello')
     })
     t.teardown(() => connection.destroy())