in js/bootstrap.bundle.js [2817:2845]
function getRoundedOffsets(data, shouldRound) {
var _data$offsets = data.offsets,
popper = _data$offsets.popper,
reference = _data$offsets.reference;
var round = Math.round,
floor = Math.floor;
var noRound = function noRound(v) {
return v;
};
var referenceWidth = round(reference.width);
var popperWidth = round(popper.width);
var isVertical = ['left', 'right'].indexOf(data.placement) !== -1;
var isVariation = data.placement.indexOf('-') !== -1;
var sameWidthParity = referenceWidth % 2 === popperWidth % 2;
var bothOddWidth = referenceWidth % 2 === 1 && popperWidth % 2 === 1;
var horizontalToInteger = !shouldRound ? noRound : isVertical || isVariation || sameWidthParity ? round : floor;
var verticalToInteger = !shouldRound ? noRound : round;
return {
left: horizontalToInteger(bothOddWidth && !isVariation && shouldRound ? popper.left - 1 : popper.left),
top: verticalToInteger(popper.top),
bottom: verticalToInteger(popper.bottom),
right: horizontalToInteger(popper.right)
};
}