/**
 * Converts a JavaScript date object to a SAS Date or Datetime, given the logic below:
 *
 * A JS Date contains the number of _milliseconds_ since 01/01/1970
 * A SAS Date contains the number of _days_ since 01/01/1960
 * A SAS Datetime contains the number of _seconds_ since 01/01/1960
 *
 * @param jsDate JS Date to be converted. The type is instance of `Date`
 * @param unit Unit in which to return the SAS Date / datetime, eg `sasdate | sasdatetime`
 * @returns SAS Date value based on `unit` param
 */
export declare const convertJsDateToSasDate: (jsDate: Date, unit: 'sasdate' | 'sasdatetime') => number;