How do I wait for websocket to connect before sending messages?

Question

I am using websockets to get data for a react-redux app I am creating, though I am currently sending executing the action the send a message, if not connected to the websocket, holding onto the message in an array then when the websocket connects (onopen) I send all messages with Date.now() of less than 10 mins ago.

Is this okay? Or is there a proper way to handle this sort of action.

---

Component

componentDidMount() {
    this.props.actions.getData()
}

Socket Handler

let heldMessages = [];
/* ...Socket setup */
socket.onopen = () => {
    if(heldMessages.length) {
        heldMessages.forEach(msg => {
            // In last 10 Minutes
            if(msg.time > (Date.now() - 600000)) {
                sendData(msg.data);
            }
       });
       heldMessages = [];
    }
}

/* ... misc functions */

function sendData(obj) {
     if(connected) {
         /* ...socket sending logic */
     } else {
         heldMessages.push({ time: Date.now(), data: obj });
     }
 }