how to return objects in array as string with comma ?

Question

var list = [ { id : 1234, shop : 'shop1' }, { id : 4312, shop : 'shop2' } ];

I want that only id attributes in object array return as "1234,4312". How can I do?

Answer 1

Even easier:

var list = [ { id : 1234, shop : 'shop1' }, { id : 4312, shop : 'shop2' } ];
ids = list.map(function(obj){
    return obj.id
})

If you specifically need a string, add a .toString() to the end of the map call:

ids = list.map(function(obj){
    return obj.id
}).toString()

Answer 2

You have to loop through the array and create a new array. It's actually not that hard:

var list = [ { id : 1234, shop : 'shop1' }, { id : 4312, shop : 'shop2' } ];
var ids = [];
list.forEach(function(obj, index){
    ids.push(obj.id);
});

if you want that as a comma delimited string you can simply call ids.toString(); it's the default behavior.