function flip()

in Hands-on lab/lab-files/BigDataTravel/BigDataTravel/Scripts/popper.js [1456:1544]
59 lines of code
54 McCabe index (conditional complexity)

function flip(data, options) {
  // if `inner` modifier is enabled, we can't use the `flip` modifier
  if (isModifierEnabled(data.instance.modifiers, 'inner')) {
    return data;
  }

  if (data.flipped && data.placement === data.originalPlacement) {
    // seems like flip is trying to loop, probably there's not enough space on any of the flippable sides
    return data;
  }

  const boundaries = getBoundaries(data.instance.popper, data.instance.reference, options.padding, options.boundariesElement, data.positionFixed);

  let placement = data.placement.split('-')[0];
  let placementOpposite = getOppositePlacement(placement);
  let variation = data.placement.split('-')[1] || '';

  let flipOrder = [];

  switch (options.behavior) {
    case BEHAVIORS.FLIP:
      flipOrder = [placement, placementOpposite];
      break;
    case BEHAVIORS.CLOCKWISE:
      flipOrder = clockwise(placement);
      break;
    case BEHAVIORS.COUNTERCLOCKWISE:
      flipOrder = clockwise(placement, true);
      break;
    default:
      flipOrder = options.behavior;
  }

  flipOrder.forEach((step, index) => {
    if (placement !== step || flipOrder.length === index + 1) {
      return data;
    }

    placement = data.placement.split('-')[0];
    placementOpposite = getOppositePlacement(placement);

    const popperOffsets = data.offsets.popper;
    const refOffsets = data.offsets.reference;

    // using floor because the reference offsets may contain decimals we are not going to consider here
    const floor = Math.floor;
    const overlapsRef = placement === 'left' && floor(popperOffsets.right) > floor(refOffsets.left) || placement === 'right' && floor(popperOffsets.left) < floor(refOffsets.right) || placement === 'top' && floor(popperOffsets.bottom) > floor(refOffsets.top) || placement === 'bottom' && floor(popperOffsets.top) < floor(refOffsets.bottom);

    const overflowsLeft = floor(popperOffsets.left) < floor(boundaries.left);
    const overflowsRight = floor(popperOffsets.right) > floor(boundaries.right);
    const overflowsTop = floor(popperOffsets.top) < floor(boundaries.top);
    const overflowsBottom = floor(popperOffsets.bottom) > floor(boundaries.bottom);

    const overflowsBoundaries = placement === 'left' && overflowsLeft || placement === 'right' && overflowsRight || placement === 'top' && overflowsTop || placement === 'bottom' && overflowsBottom;

    // flip the variation if required
    const isVertical = ['top', 'bottom'].indexOf(placement) !== -1;

    // flips variation if reference element overflows boundaries
    const flippedVariationByRef = !!options.flipVariations && (isVertical && variation === 'start' && overflowsLeft || isVertical && variation === 'end' && overflowsRight || !isVertical && variation === 'start' && overflowsTop || !isVertical && variation === 'end' && overflowsBottom);

    // flips variation if popper content overflows boundaries
    const flippedVariationByContent = !!options.flipVariationsByContent && (isVertical && variation === 'start' && overflowsRight || isVertical && variation === 'end' && overflowsLeft || !isVertical && variation === 'start' && overflowsBottom || !isVertical && variation === 'end' && overflowsTop);

    const flippedVariation = flippedVariationByRef || flippedVariationByContent;

    if (overlapsRef || overflowsBoundaries || flippedVariation) {
      // this boolean to detect any flip loop
      data.flipped = true;

      if (overlapsRef || overflowsBoundaries) {
        placement = flipOrder[index + 1];
      }

      if (flippedVariation) {
        variation = getOppositeVariation(variation);
      }

      data.placement = placement + (variation ? '-' + variation : '');

      // this object contains `position`, we want to preserve it along with
      // any additional property we may add in the future
      data.offsets.popper = _extends({}, data.offsets.popper, getPopperOffsets(data.instance.popper, data.offsets.reference, data.placement));

      data = runModifiers(data.instance.modifiers, data, 'flip');
    }
  });
  return data;
}