Retrieving javascript value in Angular Scope

Question

I have a javascript function that retrieves a JSON object and the returns that value after processing it into a dataTable. Where I am running into trouble is returning that value to an Angular Scope. How would I retrieve the returned value inside the Angular Scope function?

Javascript

    function sessionsLength(){
    loadReport('session-length', 'days', oneMonth).then(function (results) {
        var i
        var rows = [];
        for (i = 0; i < results.length; i++) {
            var c = [];
            c.push(
                {v: results[i].timestamp.valueOf()},
                {v: results[i].data.tenth},
                {v: results[i].data.fiftieth},
                {v: results[i].data.ninetieth}
            );
            var segment = {c:c};
            rows.push(segment);
        }

        var dayPlot = {
            id: 'day',
            label: 'Day',
            type: 'number'
        };

        var tenthPlot = {
            id: 'tenth',
            label: 'Tenth',
            type: 'number'
        };

        var fiftiethPlot = {
            id: 'fiftieth',
            label: 'Fiftieth',
            type: 'number'
        };

        var ninetiethPlot = {
            id: 'ninetieth',
            label: 'Ninetieth',
            type: 'number'
        };

        var cols = [dayPlot,tenthPlot,fiftiethPlot,ninetiethPlot];

        var plot = {
            type:'Line',
            data:{
                'cols':
                    cols
                ,
                'rows':
                    rows
            },
            options: {
                chart:{
                    title: '',
                    subtitle: ''
                },
                height: 500
            }
        };
        return plot;
        console.log(plot);
    });
}

Angular Controller

'use strict';

angular.module('triAngularElements').
    controller('GoogleChartsLineController', function ($scope) {
        $scope.chartData = sessionsLength();
    });