Javascript closures with google geocoder
- by DaNieL
Hi all, i still have some problems with javascript closures, and input/output variables.
Im playing with google maps api for a no profit project: users will place the marker into a gmap, and I have to save the locality (with coordinates) in my db.
The problem comes when i need to do a second geocode in order to get a unique pairs of lat and lng for a location: lets say two users place the marker in the same town but in different places, I dont want to have the same locality twice in the database with differents coords.
I know i can do the second geocode after the user select the locality, but i want to understand what am i mistaking here:
// First geocoding, take the marker coords to get locality.
geocoder.geocode(
{
'latLng': new google.maps.LatLng($("#lat").val(), $("#lng").val()),
'language': 'it'
},
function(results_1, status_1){
// initialize the html var inside this closure
var html = '';
if(status_1 == google.maps.GeocoderStatus.OK)
{
// do stuff here
for(i = 0, geolen = results_1[0].address_components.length; i != geolen)
{
// Second type of geocoding: for each location from the first geocoding,
// i want to have a unique [lat,lan]
geocoder.geocode(
{
'address': results_1[0].address_components[i].long_name
},
function(results_2, status_2){
// Here come the problem. I need to have the long_name here, and
// 'html' var should increment.
coords = results_2[0].geometry.location.toUrlValue();
html += 'some html to let the user choose the locality';
}
);
}
// Finally, insert the 'html' variable value into my dom...
//but it never gets updated!
}
else
{
alert("Error from google geocoder:" + status_1)
}
}
);
I tryed with:
// Second type of geocoding: for each location from the first geocoding, i want
// to have a unique [lat,lan]
geocoder.geocode(
{
'address': results_1[0].address_components[i].long_name
},
(function(results_2, status_2, long_name){
// But in this way i'll never get results_2 or status_2, well, results_2
// get long_name value, status_2 and long_name is undefined.
// However, html var is correctly updated.
coords = results_2[0].geometry.location.toUrlValue();
html += 'some html to let the user choose the locality';
})(results_1[0].address_components[i].long_name)
);
And with:
// Second type of geocoding: for each location from the first geocoding, i want to have
// a unique [lat,lan]
geocoder.geocode(
{
'address': results_1[0].address_components[i].long_name
},
(function(results_2, status_2, long_name){
// But i get an obvious "results_2 is not defined" error (same for status_2).
coords = results_2[0].geometry.location.toUrlValue();
html += 'some html to let the user choose the locality, that can be more than one';
})(results_2, status_2, results_1[0].address_components[i].long_name)
);
Any suggestion?
EDIT:
My problem is how to pass an additional arguments to the geocoder inner function:
function(results_2, status_2, long_name){
//[...]
}
becose if i do that with a clousure, I mess with the original parameters (results_2 and status_2)
