Angular digit negative numbers parser

function digitNegativeNumbers(): any {
  return {
    restrict: 'A',
    require: 'ngModel',
    link(scope: IScope, element: HTMLElement, attrs: any, ngModelCtrl: any) {
      function inputValue(val: string) {
        if (val) {
          const transformedValue = val.replace(/([^-\d.]+)?((-{0,1}\d*\.?\d*)(.*)?$)/, '$3');
          if (transformedValue !== val) {
            ngModelCtrl.$setViewValue(transformedValue);
            ngModelCtrl.$render();
          }
          return parseFloat(transformedValue);
        }
        return undefined;
      }
      ngModelCtrl.$parsers.push(inputValue);
    }
  };
}