The dayNames property (string[]) holds the full day-of-week names used by a locale.
DayPilot.Locale.dayNames["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"]The array items are ordered from Sunday through Saturday.
This value is used for the "dddd" date-formatting pattern supported by DayPilot.Date.toString().
const locale = new DayPilot.Locale("es-custom", {
dayNames: ["Domingo", "Lunes", "Martes", "Miercoles", "Jueves", "Viernes", "Sabado"],
// ...
});
DayPilot.Locale.register(locale);