FacetHistogramFilter.prototype._initializeDragging = function()

in lib/@uncharted.software/stories-facets/src/components/facet/facetHistogramFilter.js [126:224]
42 lines of code
7 McCabe index (conditional complexity)

FacetHistogramFilter.prototype._initializeDragging = function () {
	var calculateFrom = function (range, offset, barWidth, totalWidth) {
		range.from = Math.max(0, range.from + offset);
		if (range.from > range.to - barWidth) {
			if (range.from + barWidth < totalWidth) {
				range.to = range.from + barWidth;
			} else {
				range.from = totalWidth - barWidth;
				range.to = totalWidth;
			}
		}
	};

	var calculateTo = function (range, offset, barWidth, totalWidth) {
		range.to = Math.min(totalWidth, range.to + offset);
		if (range.to < range.from + barWidth) {
			if (range.to - barWidth > 0) {
				range.from = range.to - barWidth;
			} else {
				range.from = 0;
				range.to = barWidth;
			}
		}
	};

	var barWidth = this._histogram.barWidth;
	var totalWidth = this._histogram.totalWidth;

	var endDragging = function (event) {
		if (this._draggingLeft || this._draggingRight) {
			event.preventDefault();
			var range = {
				from: this._pixelRange.from,
				to: this._pixelRange.to
			};

			if (this._draggingLeft) {
				this._canDragLeft = false;
				this._draggingLeft = false;
				calculateFrom(range, (event.clientX - this._draggingLeftX), barWidth, totalWidth);
			}

			if (this._draggingRight) {
				this._canDragRight = false;
				this._draggingRight = false;
				calculateTo(range, (event.clientX - this._draggingRightX), barWidth, totalWidth);
			}

			this.setFilterPixelRange(range, true);
			return false;
		}
		return true;
	}.bind(this);

	this._element.mouseleave(endDragging);
	this._element.mouseup(endDragging);

	this._element.mousemove(function(event) {
		if (this._canDragLeft || this._canDragRight) {
			var range = {
				from: this._pixelRange.from,
				to: this._pixelRange.to
			};

			if (this._canDragLeft) {
				if (!this._draggingLeft) {
					this._draggingLeft = true;
				}
				calculateFrom(range, (event.clientX - this._draggingLeftX), barWidth, totalWidth);
			}

			if (this._canDragRight) {
				if (!this._draggingRight) {
					this._draggingRight = true;
				}
				calculateTo(range, (event.clientX - this._draggingRightX), barWidth, totalWidth);
			}

			var barRange = this._histogram.pixelRangeToBarRange(range);
			this.updateUI(barRange, range);
		}
	}.bind(this));

	this._leftHandle.mousedown(function (event) {
		event.preventDefault();
		this._canDragLeft = true;
		this._draggingLeft = false;
		this._draggingLeftX = event.clientX;
		return false;
	}.bind(this));

	this._rightHandle.mousedown(function (event) {
		event.preventDefault();
		this._canDragRight = true;
		this._draggingRight = false;
		this._draggingRightX = event.clientX;
		return false;
	}.bind(this));
};