Function extend

Pikaday/pikaday.js:138–161

(to, from, overwrite)

    },

    extend = function(to, from, overwrite)
    {
        var prop, hasProp;
        for (prop in from) {
            hasProp = to[prop] !== undefined;
            if (hasProp && typeof from[prop] === 'object' && from[prop] !== null && from[prop].nodeName === undefined) {
                if (isDate(from[prop])) {
                    if (overwrite) {
                        to[prop] = new Date(from[prop].getTime());
                    }
                }
                else if (isArray(from[prop])) {
                    if (overwrite) {
                        to[prop] = from[prop].slice(0);
                    }
                } else {
                    to[prop] = extend({}, from[prop], overwrite);
                }
            } else if (overwrite || !hasProp) {
                to[prop] = from[prop];
            }
        }
        return to;
    },

    adjustCalendar = function(calendar) {
        if (calendar.month < 0) {