Retrofit bindToController for Angular 1.2 Typescript

somedirective.js

export function infoChart() {
    return {
        restrict: 'A',
        scope: {
            highchartsOptions: '=',
            title: '@',
            info: '@'
        },
        templateUrl: 'template.html',
        controllerAs: 'vm',
        controller: InfoChartController,
        bindToController: true
    };
}

export class InfoChartController {
    title: string;
    constructor($scope: ng.IScope){
        this.oneWayBind($scope, 'title');
        this.twoWayBind($scope, 'info');
        this.oneWayBind($scope, 'highchartsOptions');
    }

    oneWayBind($scope: ng.IScope, keyToBind: string){
        let unbindWatcher = $scope.$watch(keyToBind, (newValue)=> {
            if(typeof(newValue) !== 'undefined'){
                this[keyToBind] = newValue;
                // unbind as soon as value is not undefined so we dont grow the $watch count
                unbindWatcher();
            }
        })
    }

    twoWayBind($scope: ng.IScope, keyToBind: string){
        $scope.$watch(keyToBind, (newValue)=> {
            if(typeof(newValue) !== 'undefined'){
                this[keyToBind] = newValue;
            }
        })
    }
}