private static addNextDaysOff()

in src/gantt.ts [1155:1196]
38 lines of code
15 McCabe index (conditional complexity)

    private static addNextDaysOff(
        daysOffDataForAddition: DaysOffDataForAddition,
        firstDayOfWeek: number,
        date: Date,
        extraCondition: boolean = false): DaysOffDataForAddition {
        daysOffDataForAddition.amountOfLastDaysOff = 1;
        for (let i = DaysInAWeekend; i > 0; i--) {
            let dateForCheck: Date = new Date(date.getTime() + (i * MillisecondsInADay));
            let alreadyInDaysOffList = false;
            daysOffDataForAddition.list.forEach((item) => {
                const itemDate = item[0];
                if (itemDate.getFullYear() === date.getFullYear() && itemDate.getMonth() === date.getMonth() && itemDate.getDate() === date.getDate()) {
                    alreadyInDaysOffList = true;
                }
            });

            const isFirstDaysOfWeek = dateForCheck.getDay() === +firstDayOfWeek;
            const isFirstDayOff = dateForCheck.getDay() === (+firstDayOfWeek + 5) % 7;
            const isSecondDayOff = dateForCheck.getDay() === (+firstDayOfWeek + 6) % 7;
            const isPartlyUsed = !/00\:00\:00/g.test(dateForCheck.toTimeString());

            if (!alreadyInDaysOffList && isFirstDaysOfWeek && (!extraCondition || (extraCondition && isPartlyUsed))) {
                daysOffDataForAddition.amountOfLastDaysOff = i;
                daysOffDataForAddition.list.push([
                    new Date(date.getFullYear(), date.getMonth(), date.getDate(), 0, 0, 0), i
                ]);
            }

            // Example: some task starts on Saturday 8:30 and ends on Thursday 8:30,
            // so it has extra duration and now will end on next Saturday 8:30
            // --- we need to add days off -- it ends on Monday 8.30
            if (!alreadyInDaysOffList && (isFirstDayOff || isSecondDayOff) && isPartlyUsed) {
                const amount = isFirstDayOff ? 2 : 1;
                daysOffDataForAddition.amountOfLastDaysOff = amount;
                daysOffDataForAddition.list.push([
                    new Date(dateForCheck.getFullYear(), dateForCheck.getMonth(), dateForCheck.getDate(), 0, 0, 0), amount
                ]);
            }
        }

        return daysOffDataForAddition;
    }