JavaScript - fetch POST request with async stored result

fetch POST request with async stored result

function myFunc(){
    if(GLOBAL.data === null){
        let formData = new FormData();
        formData.append("filters", JSON.stringify(GLOBAL.filters));
        fetch("myScript.php", {method: "POST", body: formData})
            .then((response) => {
                if (response.ok) {
                    return response.json();
                } else {
                    alert(`Error: ${response.statusText}`);
                }
            })
            .then(data => {
                GLOBAL.data = data;
            })
            .catch(function (error) {
                console.error("fetch error: " + error.message);
            });
    }
    (async() => {
        while(GLOBAL.data === null)
            await new Promise(resolve => setTimeout(resolve, 1000));
        /*

        *  here some code wich can use GLOBAL.data stored from fetch

        */
    })();
}