How to set interval for get data from API (jQuery)

Question

I have a simple question: I am using this function for getting prices from CryptoCompare and now I would like set interval for refreshing data without refreshing page. So I have tried this code:

<script>
    getData('dash', 'https://min-api.cryptocompare.com/data/price?fsym=DASH&tsyms=USD');

    function getData(prefix, url) {
      $.getJSON(url, function(data) {
        $.each(data, function(key, val) {
          $('.' + prefix + '-' + key.toLowerCase()).html(val);
        });
      });
    }
    setInterval(getData, 3000);
    $(function() {
      getData();
    });
</script>

But it is not working for me. Can you help me, please?

Answer 1

You have some convoluted code. I think what you are intending is for your fetch to be called every 3 seconds.

function getData(prefix, url) {
  $.getJSON(url, function(data) {
    $.each(data, function(key, val) {
      $('.' + prefix + '-' + key.toLowerCase()).html(val);
    });
  });
}

This defines you get function. You have a sample call as

getData('dash', 'https://min-api.cryptocompare.com/data/price?fsym=DASH&tsyms=USD');

You are using setInterval incorrectly though, see https://www.w3schools.com/jsref/met_win_setinterval.asp

You have 2 lines here

setInterval(getData, 3000);
$(function() {            getData();        });

This is incorrect, getData is only a name for your function. The setInterval function should take your anonymous function with defined parameters like

setInterval($(function() {           
  getData('dash', 'https://min-api.cryptocompare.com/data/price?fsym=DASH&tsyms=USD'); 
}), 3000);

Per your JS fiddle, this works for me (removed jquery function and replaced with regular js lambda)

function getData(prefix, url) {
  $.getJSON(url, function(data) {
    $.each(data, function(key, val) {
      $('.' + prefix + '-' + key.toLowerCase()).html(val);
    });
  });
}
setInterval(function() {    
  getData('btc', 'https://min-api.cryptocompare.com/data/price?fsym=BTC&tsyms=USD'); 
}, 3000);