Binding checkboxes to object values in AngularJs

The problem is in binding the state of the checkbox (checked/unchecked) to the object values.


<div ng:controller="Ctrl"> 
   <div ng:repeat="(letter, number) in obj">
     {{letter}} and {{number}}
     <input type="checkbox" ng:model="obj[letter]">


function Ctrl() {
    this.obj = {a:true,b:true};    

When the first checkbox is clicked it affects the state of the second checkbox, but the model is correct, so obj becomes {a:false, b:true}.

Example can be found at

How to fix this?

Bind ng-repeat to objects rather than primitive types.

function Ctrl() {
    this.obj = [{id: 'a', checked: true}, {id: 'b', checked: true}];

Binding to primitive types confuses ng-repeat, it's a bug:

When the JSON is not entirely in your control, you get a primitive array instead of an object. You want to do an ng-repeat on the same.

To bind ng-repeats to checkboxes to a primitive array and get the selected items. See the plunker code here.