How to subtract two angularjs date variables

Question

I am fairly new to angularjs, but here it goes. I am able two dates through angularjs in the form dd/mm/yyyy, but what I need to do is somehow subtract the two

Answer 1

I'm also an angularjs novice but wouldn't you handle this by making properties available through your javascript view model?

For example have a style field that changes based on the date fields (ie style returns style 1 when if the difference is 10 days) and hopefully through the angularjs binding the updates will propagate to the screen.

I think the right term for this is a computed property or calculated property

EDIT

Not sure if this is what you're looking for but see fiddle for example of calculating date diff and changing a style all based off properties of the view model (scope)

scope.diff and scope.col are the 2 properties to bind to

http://jsfiddle.net/chrismoutray/wfjv6/

HTML

    first date  second date  difference {{diff}}
    
when the difference is greater than 10 color changes to green
    
eg set the second date to 15/01/2013
    
 State 

JS

function ComputedPropertiesCtrl() {
    var scope = this;
    scope.firstdate = '01/01/2013';
    scope.seconddate = '10/01/2013';
    scope.data_before = [];
    scope.differenceInDays = function() {

        var dt1 = scope.firstdate.split('/'),
            dt2 = scope.seconddate.split('/'),
            one = new Date(dt1[2], dt1[1]-1, dt1[0]),
            two = new Date(dt2[2], dt2[1]-1, dt2[0]);

        var millisecondsPerDay = 1000 * 60 * 60 * 24;
        var millisBetween = two.getTime() - one.getTime();
        var days = millisBetween / millisecondsPerDay;

        return Math.floor(days);      
    };
    scope.color = function() {
        return (scope.differenceInDays() > 10) ? 'green' : 'red';
    };

    scope.$watch('[firstdate, seconddate]', function(currScope,newVal,oldVal) {
        scope.data_before = oldVal;
        scope.diff = scope.differenceInDays();
    });

    scope.$watch('[firstdate, seconddate]', function(currScope,newVal,oldVal) {
        scope.data_before = oldVal;
        scope.col = scope.color();
    });
}

CSS

h2 { position: fixed; right: 10px; top: 10px; color: red; background:white;z-index:1000; }
input { width: 100px; }
div { margin: 10px; padding: 10px; }