CODEWITHSUNDEEP
javascriptarraysobjectmaps
mkyong
mkyong

Reputation: 12947

Object Overwriting key-value pair in JavaScript

I'm trying to store a user ID (key) and an array of GPS coordinates using an object in JavaScript, but for some reason each time a new set of coordinates is added (when it pulls from the database), it overwrites the previous coordinates in the array (value) instead of appending. 

$(function () {
        $(document).ready(function(){
            setInterval(function(){
                $.ajax({                                      
                    url: 'api.php',                  //the script to call to get data          
                    data: "",                        
                    dataType: 'json',                //data format      
                    success: function(data){          //on recieve of reply                          
                        var loc = {};

                        user_id = data[0];
                        lati = data[1];              //get id
                        longi = data[2];           //get name

                        var myLatlngt = 'new google.maps.LatLng(' + lati + ',' + longi + ')';

                        if (typeof loc[user_id] === 'undefined') {
                            loc[user_id] = [];
                            }

                        loc[user_id].push(myLatlngt);
                        console.log('loc :::', loc);

Here's the log: 

Resource interpreted as Other but transferred with MIME type undefined.
map2.php:50loc ::: Object    
    86ad04fb-1da5-4118-8b00-942676d62387: Array[1]
        0: "new google.maps.LatLng(51,-82)"
        length: 1
    __proto__: Array[0]
__proto__: Object

The long number (86ad04...) is the user ID (key), but if I send new coordinates it overwrites instead of appending. I would appreciate any help I can get.

Thanks

Upvotes: 0

Views: 1480

Answers (2)

Dan D.
Dan D.

Reputation: 74655

you need to place var loc = {}; outside of your ajax callback so that its state is preserved over multiple ajax requests.

Upvotes: 0

Michael Krelin - hacker
Michael Krelin - hacker

Reputation: 143139

Because you empty loc every time you enter the function:

var loc = {};

Upvotes: 2

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