如何在包含此功能之外的TimeZoneDB API响应的jQuery函数中获取变量的值或数组？

Question

I'm new in programming and have a little problem. I'm programming a map in which you can get the next overflight of a specific satellite by clicking in a map. But the timestamp in the acquisition plan of this satellite is written in UTC. Therefore, I'm calculating the time difference/zone of this location with the TimeZoneDB API ( https://timezonedb.com/api ). The request is send by clicking in the map and the response is the current time and date of this location in JSON format in the attribute formatted. This timestamp will be substracted from the UTC time. The final time zone is shown in a popup, then. But I have the problem, I don't get the variable with the current date global. I've tried to save it in the local storage and recall it, which works fine, but doesn't look good. And by using this way another problem faces up. Sometimes showing the popup content is faster than the response of the server and shows no value. My JavaScript/jQuery code of sending the request and getting the date in a variable looks like this (the API key, longitude and latitude were defined in variables before this jQuery function):

$.getJSON("http://api.timezonedb.com/v2/get-time-zone?key="+key+"&format=json&by=position&lat="+lat+"&lng="+lon, function(localdata) {
localtime = localdata.formatted;
localStorage.setItem('loct', localtime);
});

var localtime = localStorage.getItem('loct');
localtime = new Date (localtime);
localtime = localtime.getTime();
localStorage.removeItem('loct');

I know there might be similar questions, but I didn't get to solve it by a callback function. I guess I'm doing something wrong. It will be great if somebody can help me :-)

Best regards Anna

Answer 1

Something like this not tested

    function getTimeZone(key, lat, lon, callback) {
    $.getJSON("http://api.timezonedb.com/v2/get-time-zone?key=" + key + "&format=json&by=position&lat=" + lat + "&lng=" + lon, function (localdata) {
        localtime = localdata.formatted;
        localStorage.setItem('loct', localtime);
        if (typeof callback == 'function') callback(localtime);
    });
}

var localtime = localStorage.getItem('loct');

if (!localtime) {
    //key,lat,lon you obviously have this set somewhere
    getTimeZone(key, lat, lon, function (localtime) {

        localtime = new Date(localtime);
        localtime = localtime.getTime();
        console.log("localtime", localtime)
        localStorage.removeItem('loct');
    })
}

You could clean that up by checking if localstorage loct key doesn't exist then call the getTimeZone...