using variables in javascript

Question

From the google maps API documentation I have got this working:

var flightPlanCoordinates = [
    new google.maps.LatLng(37.772323, -122.214897),
    new google.maps.LatLng(21.291982, -157.821856),
    new google.maps.LatLng(-18.142599, 178.431),
    new google.maps.LatLng(-27.46758, 153.027892)
  ];

what ive tried to do is replicate this piece of code with my own loop so I can use previously stored co-ords, like so:

var output;
$.getJSON('DisplayMap.php',  function(data) {
        var output = "[ ";
        for (var i in data.b) {
            output+= "new google.maps.LatLng" + "(" + data.b[i].Ya + ", " + data.b[i].Za + ")," + " ";
        }

       output+= "]";
        document.getElementById("placeholder").innerHTML=output;
    alert(output);
  });


                output+= "]";

Ive checked the output and it looks exactly as I want it to. however, when I substitute it in like this is doesnt work:

var flightPlanCoordinates = output;

Welcome to the wonderful world of async! You can't do that. — SLaks
– SLaks, Commented Jan 6, 2013 at 22:59

James Montagne · Accepted Answer · 2013-01-06 23:04:03Z

3

In your new code you are building a string instead of an array. You should have something like this instead:

var output = [];

for (var i in data.b) {
    output.push(new google.maps.LatLng(data.b[i].Ya, data.b[i].Za));
}

In addition, I am slightly confused by the fact that you create a variable named output both inside and outside of getJSON. Keep in mind that getJSON is asynchronous and you will not be able to use the variable from within getJSON immediately after it is called.

answered Jan 6, 2013 at 23:04

James Montagne

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2 Comments

Matt Jameson Over a year ago

thanks both. So now I have the code you've provided how would I layout the var flightPlanCoordinates = [ new google.maps.LatLng(37.772323, -122.214897), new google.maps.LatLng(21.291982, -157.821856), new google.maps.LatLng(-18.142599, 178.431), new google.maps.LatLng(-27.46758, 153.027892) ];

Matt Jameson Over a year ago

i got it. GET int there. Cheers folks

The Alpha · Accepted Answer · 2013-01-06 23:16:07Z

2

You have to set up a correct javascript Array instead of a string. Like this:

var output = [];
$.getJSON('DisplayMap.php',  function(data) {
        for (var i in data.b) {
            output.push(new google.maps.LatLng(data.b[i].Ya, data.b[i].Za));
        }
  });

edited Jan 6, 2013 at 23:16

The Alpha

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answered Jan 6, 2013 at 23:05

Thomas Kekeisen

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