#useWebSocketLatency

Read round-trip time and server clock offset from createWebSocketLatency.

function useWebSocketLatency(latency: WebSocketLatency): Latency;

#Usage

import { useWebSocketLatency } from 'react-websocket';
import { latency } from './latency';

function Ping() {
  const { rtt } = useWebSocketLatency(latency);
  return <span>{rtt === undefined ? '–' : `${Math.round(rtt)} ms`}</span>;
}

#Parameters

#Returns

Latency: { rtt, offset }, both in ms, both undefined until the first pong.

#Behavior

• Renders. It re-renders when a measurement changes, about once per ping interval.
• Connection. It holds the client connection while mounted, like the other hooks.
• Server rendering. On the server and during hydration, both values are undefined.
• Server time. For the server's clock, call latency.serverNow() where you need it, such as in a timer or animation frame, instead of rendering offset.