test: replace typeof undefined check (#272)

* test: replace `typeof` undefined check

* simplify

---------

Co-authored-by: Aras Abbasi <aras.abbasi@googlemail.com>

Author: Fdawgs

test/base.test.js

@@ -324,12 +324,7 @@ test('Should be able to pass custom connectionOptions to createWebSocketStream',
   })
 
   fastify.get('/', { websocket: true }, (connection) => {
-    // 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)
+    t.equal(connection.readableObjectMode, true)
     connection.socket.binaryType = 'arraybuffer'
 
     connection.once('data', (chunk) => {