How do I identify checkbox value with given HTML element? angularjs-e2e

I need some advice with issue below. When checkbox = checked, there will be attribute value checked=checked and for the unchecks, attribute will not be there and I can't uniquely identify. On a page, there will be checked and unchecked checkboxes. Dev refuses to add additional attribute for me and saying that there must be a way to identify (exist or not exist).

So on my my test page, I have 10 checkboxes with 3 checked and 7 unchecked.

HTML for uncheck checkboxes

<input type="checkbox" disabled="disabled" ng-checked="item.unread">

HTML for checked checkboxes

<input type="checkbox" disabled="disabled" ng-checked="item.unread" checked="checked">

My attempt at counting - it will returned exact number and will fail eventually as number may change.

expect(element.all(by.css('input[checked="checked"]')).count()).toBe(2);

No issue with identifying checked items with attribute - checked="checked"

expect(element.all(by.css('input[checked="checked"]')).isSelected()).toBeTruthy();

but fails when I check for unchecked item.

expect(element.all(by.css('input[type="checkbox"]')).isSelected()).toBeFalsy();

Failed result for unchecked item - 7 unchecked and 3 checked

[ false false false false true true false false true false]

Thanks