How do I code a custom ordering function in angular?

Question

Having

<div class="item" data-ng-repeat="course in courses | filter:filterCourses | orderBy:predicate">...

and

$scope.predicate = function(course) {
    //$scope.orderProp
};

what code do I need to put inside the predicate so I can

1. order the same way the default orderBy:predicate will order(not sure if this makes sense)
2. place empty course.StartDate at the end of the list

Notes:

• course is an Object with different properties like title, startDate, code
• $scope.orderProp contains the value to sort by: title, startDate, code. When startDate is empty I would like to place those items at the end of the list but still keep sorting by date properly, start date is an "integer" that I later display with ng-date in nicer form

Thank you

Answer: Here's what I ended up with http://jsfiddle.net/3hz2j8j7/

Answer 1

OrderBy can accept a list of predicates (a bit like saying "order by A, then B"). So your first predicate will ensure that blank start dates go at the end, and your second one will use the value of orderProp:

<div ... orderBy:[nonEmptyStartDate, orderProp]">

$scope.nonEmptyStartDate = function(course) {
    return course.startDate=="" ? 1 : 0;
}