Hi,
You don't need a Hash, the "children" objects are Arrays, which means
they'll have the Enumerable#each[1] function mixed in with them.
Also, if you're using Prototype 1.6 and returning the correct content-
type, you don't need to use transport.responseText.evalJSON -- just
use transport.responseJSON, it's already been done. But regardless of
which way you do it, eventually you end up with a 'json' var pointing
to that structure.
If you already know that you'll be getting back a category
("Products") with one sub-category ("Furniture") and that you want to
loop through the children of that sub-category, you can get a
reference to them like so:
var children = json.children[0].children;
If not (if id:3 may be anywhere in the structure), you'll have to go
looking for it, perhaps with recursive descent, something like this
(largely untested):
* * * *
function findEntry(obj, id) {
var rv, children, n;
if (obj.id == id) {
rv = obj;
} else {
rv = undefined;
children = obj.children;
if (children && children.length > 0) {
for (n = children.length - 1; !rv && n >= 0; --n) {
rv = findEntry(children[n], id);
}
}
}
return rv;
}
* * * *
Once you've found the object that has the children, looping through
them is trivial. Either a boring old-fashioned loop like the one in
findEntry above, or you could use Enumerable#each like this:
* * * *
obj.children.each(function(child) {
alert(child.name);
});
* * * *
So putting it all together:
* * * *
onSuccess: function(transport) {
var json = transport.responseJSON;
var obj = findEntry(json, 3);
if (obj) {
obj.children.each(function(child) {
alert(child.name);
});
}
}
* * * *
You might also want to look at some of the other Enumerable methods,
like #pluck[2], depending on what it is you want to do with the child
names.
[1] http://prototypejs.org/api/enumerable/each
[2] http://prototypejs.org/api/enumerable/pluck
HTH,
--
T.J. Crowder
tj / crowder software / com
Independent Software Engineer, consulting services available
On Jul 6, 2:09 am, seamusjr <[email protected]> wrote:
> I am trying to get a collection of objects in JSON that have children
> and iterate through the name properties of those children. For
> example I want to get the collection of Furniture and return its
> children.
>
> I have tried to do this by converting the Object to a Hash and iterate
> through it with an each. It seems to get the Objects but returns them
> as undefined.
>
> How can I return the names of the children in id:3 as strings?
>
> Thanks,
> Seamus
>
> sample.json:
>
> {
> "id": 2,
> "name": "Products",
> "children": [
> { "id": 3, "name": "Furniture", "children":
> [
> { "id": 4, "name": "Table", children: []},
> { "id": 5, "name": "Chair", children: []},
> { "id": 6, "name": "Lamp", children: []},
>
> ]
> }
> ]
>
> }
>
> ajax.js:
>
> var SomeObj = Class.create();
> SomeObj.prototype = {
> initialize: function(){
> console.log("Hello");
> },
>
> getStuff: function(){
> new Ajax.Request('/sample.json',
> {
> method:'get',
> onSuccess: function(transport){
> var json = transport.responseText.evalJSON();
> $H(json).each(function(element){
> console.log(json.children.name);
> });
>
> },
>
> onFailure: function(){ console.log('Something went wrong...') }
> });
>
> }
>
> }
>
> Event.observe(document, "dom:loaded", function(){
> someObj = new SomeObj;
> someObj.getStuff();
>
>
>
> });
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