titleFormat 1.1

Determines the text that will be displayed in the header’s title.

{
  month: 'MMMM yyyy',                             // September 2009
  week: "MMM d[ yyyy]{ '—'[ MMM] d yyyy}", // Sep 7 - 13 2009
  day: 'dddd, MMM d, yyyy'                  // Tuesday, Sep 8, 2009
}

A single string will set the title format for all views. A View Option Hash may be provided to target specific views (this is what the default does).

Uses formatDate/formatDates formatting rules. (The formatting rules were much different in versions before 1.3. See here)