title: node-redis Does retry_strategy have a default value?
body: <p>Redis connection was valid even when redis-server was stopped and
  restarted without the retry_strategy option.</p>
  <pre><code>const conn = redis.createClient({
      host: 'redisUrl',
      port: 'redisPort',
      ...
      socket_keepalive : true   
  });
  
  redisClient.on('connect', () =&gt; {
      console.log(`connect`);
  }).on('error', () =&gt; {
      console.log(`error`);
  });
  </code></pre>
  <p>Why?</p>