How to make javascript fetch synchronous?

Question

I'm using fetch to get data json from an api. Works fine but I have to use it repeatedly for various calls, thus it needs to be synchronous or else I need some way to update the interface when the fetch completes for each component.

function fetchOHLC(yUrl){
    fetch(yUrl)
    .then(response => response.json())
    .then(function(response) {
                alert(JSON.stringify(response.query));

            var t = response.created;
            var o = response.open;
            var h = response.high;
            var l = response.low;
            var c = response.close;
        
        return {t,o,h,l,c};
    
    })
    .catch(function(error) {
        console.log(error);
    });    
}

var fetchData = fetchOHLC(yUrl);
alert(fetchData); // empty ?

Is there any other way to achieve it other than using fetch? (I don't want to use jquery preferrably).

Thanks

Edit

The question is about fetch-api, not ajax, not jquery, so please stop marking it as duplicate of those questions without reading it properly.

Answer 1

Callbacks and webworkers instead of the fetch API. https://developer.mozilla.org/en-US/docs/Web/API/MutationObserver

Answer 2

fetch is intended to do asynchronous calls only, but the are some options:

Option 1

If XMLHttpRequest is also fine, then you can use async: false, which will do a synchronous call.

Option 2

Use async/await which is asynchronous under the hood, but feels like it is synchronous, see https://stackoverflow.com/a/54950884/2590616

Option 3

or else I need some way to update the interface when the fetch completes for each component

This sound like fetch + Promise.all() would be a good fit, see https://stackoverflow.com/a/52013616/2590616