I tried developing browser geolocation, but it seems geolocation quickly return a value when it is still searching for my location.

Example of my script:

function updateCoordinate() {
        navigator.geolocation.getCurrentPosition(
                function (position) {
                    setTimeout(function() {
                        var returnValue = {
                            latitude: position.coords.latitude,
                            longitude: position.coords.longitude
                        }
                        var serializeCookie = serialize(returnValue);
                        $.cookie('geolocation', serializeCookie);
                        return serializeCookie;
                    }, 5000);
                },
                function () {
                    alert('Sorry, we are failed to get your location')
                }, {timeout: 5000}
        )
    }

If we execute this script updateCoordinate, the function will return undefined. But after a moment if we check the cookie it set right the coordinate.

How to make getCurrentPosition waiting until get exact coordinate before returning the value?

I tried developing browser geolocation, but it seems geolocation quickly return a value when it is still searching for my location.

Example of my script:

function updateCoordinate() {
        navigator.geolocation.getCurrentPosition(
                function (position) {
                    setTimeout(function() {
                        var returnValue = {
                            latitude: position.coords.latitude,
                            longitude: position.coords.longitude
                        }
                        var serializeCookie = serialize(returnValue);
                        $.cookie('geolocation', serializeCookie);
                        return serializeCookie;
                    }, 5000);
                },
                function () {
                    alert('Sorry, we are failed to get your location')
                }, {timeout: 5000}
        )
    }

If we execute this script updateCoordinate, the function will return undefined. But after a moment if we check the cookie it set right the coordinate.

How to make getCurrentPosition waiting until get exact coordinate before returning the value?

• javascript
• geolocation

• it does wait for the correct position, but it's asynchronous, not only that, but you have a five second delay before you write the cookie that you yourself created with a timeout ? – adeneo Commented Nov 23, 2013 at 18:24
• yes, i tried use timeout to make sure the browser get the position. but still it return undefined. – GusDeCooL Commented Nov 23, 2013 at 18:30
• Once again, it's asynchronous, and you can't return a value from an async function like that. – adeneo Commented Nov 23, 2013 at 18:32
• Forget the timeout, you need a callback. – Andy Commented Nov 23, 2013 at 18:32
• @Andy Can you please give example how to write callback for it? – GusDeCooL Commented Nov 23, 2013 at 18:34

1 Answer 1

Use a callback, not a timeout which will end you up in all sorts of problems. Something along the lines of:

// Here you pass a callback function as a parameter to `updateCoordinate`.
updateCoordinate(function (cookie) {
  console.log(cookie);
});

function updateCoordinate(callback) {
    navigator.geolocation.getCurrentPosition(
      function (position) {
        var returnValue = {
          latitude: position.coords.latitude,
          longitude: position.coords.longitude
        }
        var serializeCookie = serialize(returnValue);
        $.cookie('geolocation', serializeCookie);

        // and here you call the callback with whatever
        // data you need to return as a parameter.
        callback(serializeCookie);
      }
    )
}