Pager $watchers will not fire if sum of totalItems and page size stays the same

[igormalyk]

As mentioned by @c0bra at brianchance@45e1b5c#commitcomment-8565148

if decrement and increment of the totalItems and page size don't change the overall sum within one digest cycle then watchers will not fire. Changing the $watch expression to a function which compares string values fixes this.

[igormalyk]

@c0bra, isn't a solution to a problem you mentioned ? Is this commit good to be merged or should it be improved ?

[c0bra]

@igormalyk I think the right thing to do would be to have the $watch be on a function that returns an object containing the current page and page-size options, like so:

$scope.$watch(function() {
    return {
        a:  $scope.grid.options.pagingCurrentPage,
        b: $scope.grid.options.pagingPageSize
    };
}, function () { ... })

This jsperf test shows that there's an 80% performance hit by doing explicit string conversions: http://jsperf.com/ui-grid-paging-watch-method

[igormalyk]

Didn't think about performance at that time. You are right, @c0bra solution with objects is much better.

[c0bra]

@igormalyk I wasn't intending for you to close this. Switching it over to using an function in the $watch should be pretty straightforward. I still think we need this PR!