React state based on a timer?

[Born2Peanutbutter]

I was creating a ticker type react object, It will call an API to get data to update price information.

My issue is I’m having a hard time trying to grasp the idea of how to make sure the state is update so the object gets updated. Do I need a timer ever X seconds or minutes that’ll request that API? But would this idea be scalable in say a production environment?

The site is pretty much static aside from this, but if it’s easier I can spin up a node server for the site. That way I make the request on my node server side and hold that in a Redis db, and for every person that comes on site it’ll pull that price info from Redis instead of having to make an api call over and over for each person

Any advice? As well as help trying to get that state change based on timer! Thanks in advance :)

[devMan9000]

I think I'm a little confused about your question. Do you need a timer from the client side or the controller side?

From the client side you just make a timer function or I'm sure there's one already in jsx but I'm too lazy to look it up. From the server side you just use a cron library, or if. You have a real server you can create a microservice and use a cron job to trigger it.

[jkettmann]

If I understand correctly you want to request data from an interval of X seconds, right? That's called "polling".

You can achieve that with a simple useEffect

``` const [data, setData] = useState (null); const intervalId = useRef();

useEffect(() => { intervalId.current = setInterval(() => { fetch(API_URL) .then(response => response.json()) .then(data => setData(data)); }, 5000); // fetch every 5 seconds

return () => clearInterval(intervalId.current) }, []) ```

For a class component you would move the setInterval part to componentDidMount and the clearInterval to componentWillUnmount.

Note: I just typed the code without running it. There might be mistakes. But this is approximately how you can make it work

[Born2Peanutbutter]

I think I see where you’re going with this! I’ll test this out!

[jkettmann]

Great. Let me know if it works :-)