Passing data to callback functions? - google-maps-api-3

Question

var unique_interests = window.facebook_interests.filter((v, i, a) => a.indexOf(v) === i);
var input = map.getCenter();
var a = input.lat();
var b = input.lng();
var latlng = {lat: a, lng: b};
window.markersGP = [];
for(var i=0; i<unique_interests.length; i++)
{
var request = {
location: latlng,
radius: '500',
query: unique_interests[i]
};
console.log(request);
service = new google.maps.places.PlacesService(map);
service.textSearch(request, function (results, status){
alert(request.query);
});
}
Whenever the callback functions are called, the for loop has executed completely, and the alert() always prints out the last value in the array. Is there any way to bind the data with the function call?

Answer 1

You can apply IIFE pattern:
https://en.wikipedia.org/wiki/Immediately-invoked_function_expression
So the code sould be like:
for(var i=0; i<unique_interests.length; i++){
var request = {
location: latlng,
radius: '500',
query: unique_interests[i]
};
console.log(request);
(function (req) {
var service = new google.maps.places.PlacesService(map);
service.textSearch(req, function (results, status){
alert(req.query);
});
})(request);
}