(function(document, history, location)()

in amplify-theme/assets/js/scripts.js [4:83]
2 lines of code
2 McCabe index (conditional complexity)

(function(document, history, location) {
	
	var HISTORY_SUPPORT = !!(history && history.pushState);
  
	var anchorScrolls = {
	  ANCHOR_REGEX: /^#[^ ]+$/,
	  OFFSET_HEIGHT_PX: 70,
  
	  /**
	   * Establish events, and fix initial scroll position if a hash is provided.
	   */
	  init: function() {
		this.scrollToCurrent();
		window.addEventListener('hashchange', this.scrollToCurrent.bind(this));
		document.body.addEventListener('click', this.delegateAnchors.bind(this));
	  },
  
	  /**
	   * Return the offset amount to deduct from the normal scroll position.
	   * Modify as appropriate to allow for dynamic calculations
	   */
	  getFixedOffset: function() {
		return this.OFFSET_HEIGHT_PX;
	  },
  
	  /**
	   * If the provided href is an anchor which resolves to an element on the
	   * page, scroll to it.
	   * @param  {String} href
	   * @return {Boolean} - Was the href an anchor.
	   */
	  scrollIfAnchor: function(href, pushToHistory) {
		var match, rect, anchorOffset;
  
		if(!this.ANCHOR_REGEX.test(href)) {
		  return false;
		}
  
		match = document.getElementById(href.slice(1));
  
		if(match) {
		  rect = match.getBoundingClientRect();
		  anchorOffset = window.pageYOffset + rect.top - this.getFixedOffset();
		  window.scrollTo(window.pageXOffset, anchorOffset);
  
		  // Add the state to history as-per normal anchor links
		  if(HISTORY_SUPPORT && pushToHistory) {
			history.pushState({}, document.title, location.pathname + href);
		  }
		}
  
		return !!match;
	  },
  
	  /**
	   * Attempt to scroll to the current location's hash.
	   */
	  scrollToCurrent: function() {
		this.scrollIfAnchor(window.location.hash);
	  },
  
	  /**
	   * If the click event's target was an anchor, fix the scroll position.
	   */
	  delegateAnchors: function(e) {
		var elem = e.target;
  
		if(
		  elem.nodeName === 'A' &&
		  this.scrollIfAnchor(elem.getAttribute('href'), true)
		) {
		  e.preventDefault();
		}
	  }
	};
  
	window.addEventListener(
	  'DOMContentLoaded', anchorScrolls.init.bind(anchorScrolls)
	);
  })(window.document, window.history, window.location);