smoothScroll.animateScroll = function()

in assets/js/plugins/smooth-scroll.js [405:502]
3 lines of code
4 McCabe index (conditional complexity)

		smoothScroll.animateScroll = function (anchor, toggle, options) {

			// Cancel any in progress scrolls
			smoothScroll.cancelScroll();

			// Local settings
			var _settings = extend(settings || defaults, options || {}); // Merge user options with defaults

			// Selectors and variables
			var isNum = Object.prototype.toString.call(anchor) === '[object Number]' ? true : false;
			var anchorElem = isNum || !anchor.tagName ? null : anchor;
			if (!isNum && !anchorElem) return;
			var startLocation = window.pageYOffset; // Current location on the page
			if (_settings.header && !fixedHeader) {
				// Get the fixed header if not already set
				fixedHeader = document.querySelector(_settings.header);
			}
			var headerHeight = getHeaderHeight(fixedHeader);
			var endLocation = isNum ? anchor : getEndLocation(anchorElem, headerHeight, parseInt((typeof _settings.offset === 'function' ? _settings.offset(anchor, toggle) : _settings.offset), 10), _settings.clip); // Location to scroll to
			var distance = endLocation - startLocation; // distance to travel
			var documentHeight = getDocumentHeight();
			var timeLapsed = 0;
			var speed = getSpeed(distance, _settings);
			var start, percentage, position;

			/**
			 * Stop the scroll animation when it reaches its target (or the bottom/top of page)
			 * @param {Number} position Current position on the page
			 * @param {Number} endLocation Scroll to location
			 * @param {Number} animationInterval How much to scroll on this loop
			 */
			var stopAnimateScroll = function (position, endLocation) {

				// Get the current location
				var currentLocation = window.pageYOffset;

				// Check if the end location has been reached yet (or we've hit the end of the document)
				if (position == endLocation || currentLocation == endLocation || ((startLocation < endLocation && window.innerHeight + currentLocation) >= documentHeight)) {

					// Clear the animation timer
					smoothScroll.cancelScroll(true);

					// Bring the anchored element into focus
					adjustFocus(anchor, endLocation, isNum);

					// Emit a custom event
					emitEvent('scrollStop', _settings, anchor, toggle);

					// Reset start
					start = null;
					animationInterval = null;

					return true;

				}
			};

			/**
			 * Loop scrolling animation
			 */
			var loopAnimateScroll = function (timestamp) {
				if (!start) { start = timestamp; }
				timeLapsed += timestamp - start;
				percentage = speed === 0 ? 0 : (timeLapsed / speed);
				percentage = (percentage > 1) ? 1 : percentage;
				position = startLocation + (distance * easingPattern(_settings, percentage));
				window.scrollTo(0, Math.floor(position));
				if (!stopAnimateScroll(position, endLocation)) {
					animationInterval = window.requestAnimationFrame(loopAnimateScroll);
					start = timestamp;
				}
			};

			/**
			 * Reset position to fix weird iOS bug
			 * @link https://github.com/cferdinandi/smooth-scroll/issues/45
			 */
			if (window.pageYOffset === 0) {
				window.scrollTo(0, 0);
			}

			// Update the URL
			updateURL(anchor, isNum, _settings);

			// If the user prefers reduced motion, jump to location
			if (reduceMotion()) {
				window.scrollTo(0, Math.floor(endLocation));
				return;
			}

			// Emit a custom event
			emitEvent('scrollStart', _settings, anchor, toggle);

			// Start scrolling animation
			smoothScroll.cancelScroll(true);
			window.requestAnimationFrame(loopAnimateScroll);

		};