Get values from ng-repeater - angularjs

Question

I am trying to get the id value from each row in a ng-repeater into an input type="text" to be able to save the sort order of the table. But I don't know how to just extract the id, so I get the full vlaue of the list.
The table looks like this:
<table class="table table-striped">
<thead>
<tr>
<th class="position"></th>
<th>Specification Title</th>
<th>Last modified</th>
<th class="right">Used in</th>
</tr>
</thead>
<tbody ui-sortable="sortableOptions" ng-model="specsList">
<tr ng-repeat="spec in specsList">
<td class="position draggable"></td>
<td>{{spec.title}}</td>
<td>{{spec.lastModified}}</td>
<td class="right color_green"><strong>{{spec.usedIn}}</strong> of 12 products</td>
</tr>
</tbody>
</table>
And the input:
<input type="text" id="tableSortOrder" value="{{specsList}}">
Current value in the input text:
[{"id":"123","title":"Brand","lastModified":"2012-08-14","usedIn":"7"},{"id":"789","title":"Amount","lastModified":"2010-07-22","usedIn":"5"},{"id":"456","title":"ISBN","lastModified":"2010-02-24","usedIn":"2"}]
What I want to achieve:
123, 789, 456
Thanks for any help!

Answer 1

Is this what you want?:
<input type="text" id="tableSortOrder" value="{{ specsList.map(function(item){return item.id;}).join() }}" />
You could do that in a filter too, like this:
<input type="text" id="tableSortOrder" value="{{ specsList | splitIds }}" />
app.filter('splitIds', function() {
return function(ArrayWithIds) {
return ArrayWithIds.map(function(item){return item.id;}).join();
};
});
I've made this jsfiddle so that you can see how it works: http://jsfiddle.net/d5ye9mus/2/