mdb-reader/lib/browser/data/datetime.js

JavaScript library to read data from Access databases

export function readDateTime(buffer) {
    const td = buffer.readDoubleLE();
    const daysDiff = 25569; // days between 1899-12-30 and 01-01-19070
    return new Date(Math.round((td - daysDiff) * 86400 * 1000));
}