Javascript: Array overriding the same values after assinging to JSON object - json

Question

I am working with jquery ajax & the ajax response is multidimensional json array, I am assinging the JSON values to coordinates array & then assinging coordinates array to new JSON coord_set, after assinging all values to coord_set, It takes last array values to all,
for e.g.
the JSON result contains following values
obj[0]={125, 343, 456, 453},
obj[1]={345, 657, 234, 787},
obj[2]={980, 677, 657, 568}
after assinging to new JSON the values are:
coord_set[0] = {
fillColor : 'rgba(255, 234, 111 ,0.5)',
data : [980, 677, 657, 568]
}
coord_set[1] = {
fillColor : 'rgba(255, 234, 111 ,0.5)',
data : [980, 677, 657, 568]
}
coord_set[2] = {
fillColor : 'rgba(255, 234, 111 ,0.5)',
data : [980, 677, 657, 568]
}
This is my code:
var obj = JSON.parse(data);
for(var j=0;j<obj.length;j++)
{
for (var i=0;i<obj[j].length;i++)
{
coordinates[i] = obj[j][i].how_many;
}
coord_set[j] = { fillColor : 'rgba(255, 234, 111 ,0.5)', data : coordinates };
}
alert(JSON.stringify(coord_set));
Please tell me, If I am doing Anything wrong in my code?

Answer 1

The problem is that you're using a single coordinates array. You keep setting and re-setting the values in that same array, and you keep storing that same array in new elements of coord_set. To fix this, you just need to use a new coordinates array on each pass through the outer loop:
for(var j=0;j<obj.length;j++)
{
coordinates = []; // <----- add this
for (var i=0;i<obj[j].length;i++)

Answer 2

I'm gonna assume that JSON.parse actually works... but since you said you are using jquery, i would use http://api.jquery.com/jQuery.parseJSON/ personally...
Few things about your code:
you never create a new object for coordinates, which is, by default, a global variable in JS. You must type:
var coordinates = []; // before the for (var i = 0; ...
where is this property "how_many" coming from? I don't see it in your first block of code... The code in your i loop should be:
coordinates[i] = obj[j][i];
finally, why do you need a copy of this transient object anyway? That should just do it:
coord_set[j] = { fillColor : 'rgba(255, 234, 111 ,0.5)', data : obj[j] };
// if you change your result set to give a code like that:
obj[0]= [ 125, 343, 456, 453 ] // and not: obj[0]={125, 343, 456, 453}