Group.prototype._performDragging = function()

in lib/@uncharted.software/stories-facets/src/components/group.js [1007:1077]
52 lines of code
10 McCabe index (conditional complexity)

Group.prototype._performDragging = function (event) {
	/* calculate the group dimensions */
	var groupOffset = this._element.offset();
	var groupTop = groupOffset.top;
	var groupHeight = this._element.height();

	/* calculate the new position */
	var newTop, newLeft;
	if (event.type === 'scroll') {
		var contentOffset = this._groupContent.offset();
		newTop = contentOffset.top - groupTop - this._draggingYOffset;
		newLeft = contentOffset.left - groupOffset.left;
	} else {
		newTop = event.clientY - this._draggingY;
		newLeft = event.clientX - this._draggingX;
	}

	/* calculate the scroll offset, if any */
	this._draggingYOffset += this._draggingGroupTop - groupTop;
	this._draggingGroupTop = groupTop;
	newTop += this._draggingYOffset;

	/* calculate the content dimensions */
	var contentTop = groupTop + newTop;
	var contentMiddle = contentTop + (groupHeight * 0.5);

	/* retrieve all the groups */
	var groups = this._widget._groups;

	/* iterate through the groups */
	for (var i = 0, n = groups.length; i < n; ++i) {
		var group = groups[i];
		/* get the target group measurements */
		var targetHeight = group._element.height();
		var targetTop = group._element.offset().top;
		var targetBottom = targetTop + targetHeight;
		var targetAreaThreshold = Math.min(targetHeight, groupHeight) * 0.5;

		if ((groupTop > targetTop && contentMiddle >= targetTop - targetAreaThreshold && contentMiddle <= targetTop + targetAreaThreshold) ||
			(groupTop < targetTop && contentMiddle >= targetBottom - targetAreaThreshold && contentMiddle <= targetBottom + targetAreaThreshold)){
			if (group !== this) {
				var targetOffset = 0;
				if (targetTop < groupTop) {
					group._element.before(this._element);
					targetOffset = (targetTop - groupTop);
					this._draggingY += targetOffset;
					newTop -= targetOffset;
				} else {
					group._element.after(this._element);
					targetOffset = (targetTop - groupTop) - (groupHeight - targetHeight);
					this._draggingY += targetOffset;
					newTop -= targetOffset;
				}
				this._draggingGroupTop = this._element.offset().top;

				/* update the group indices */
				this._widget.updateGroupIndices();
			}
			break;
		}
	}

	/* apply the new position */
	this._groupContent.css({
		top: newTop,
		left: newLeft
	});

	/* trigger the drag move event */
	this.emit('facet-group:dragging:move', event, this._key);
};