Function addSubtract

tests/test_code/js/moment/moment.js:3587–3611

(mom, duration, isAdding, updateOffset)

    }

    function addSubtract(mom, duration, isAdding, updateOffset) {
        var milliseconds = duration._milliseconds,
            days = absRound(duration._days),
            months = absRound(duration._months);

        if (!mom.isValid()) {
            // No op
            return;
        }

        updateOffset = updateOffset == null ? true : updateOffset;

        if (months) {
            setMonth(mom, get(mom, 'Month') + months * isAdding);
        }
        if (days) {
            set$1(mom, 'Date', get(mom, 'Date') + days * isAdding);
        }
        if (milliseconds) {
            mom._d.setTime(mom._d.valueOf() + milliseconds * isAdding);
        }
        if (updateOffset) {
            hooks.updateOffset(mom, days || months);
        }
    }

    var add = createAdder(1, 'add'),
        subtract = createAdder(-1, 'subtract');