lazy variable initialization factory for AngularJS

lazyVariable.js

/*  
    Uses the technique at: http://michaux.ca/articles/lazy-function-definition-pattern
    Just declare this factory in your project.
    Then to use it, inject it into the controller/directive/service where its required and use it like so:
    
    var myLazyVar = lazyVariable(function(){
        //some heavy calculation here
        return value;
    });
    
    myLazyVar(); //first time does calculation
    myLazyVar(); //all successive calls to myLazyVar() will just return the calculated value
*/
    
.factory('lazyVariable', [function() {
    return function lazyVariable(valueGenerationFunc) {
        var lazyVariableInner = function() {
            var value = valueGenerationFunc.call(null);
            lazyVariableInner = function() {
                return value;
            };
            return lazyVariableInner();
        };
        return function lazyVariableWrapper() {
            return lazyVariableInner();
        };
    };
}]);