将数据传递给回调函数？

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);  
    });
}

每当调用回调函数时，for循环就完全执行了，alert()总是打印出数组中的最后一个值。有没有办法用函数调用绑定数据？

Answer 1

您可以申请IIFE模式：

https://en.wikipedia.org/wiki/Immediately-invoked_function_expression

所以代码应该是：

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);
}