function cueAutoSlide()

in js/reveal.js [4803:4872]
27 lines of code
16 McCabe index (conditional complexity)

	function cueAutoSlide() {

		cancelAutoSlide();

		if( currentSlide && config.autoSlide !== false ) {

			var fragment = currentSlide.querySelector( '.current-fragment' );

			// When the slide first appears there is no "current" fragment so
			// we look for a data-autoslide timing on the first fragment
			if( !fragment ) fragment = currentSlide.querySelector( '.fragment' );

			var fragmentAutoSlide = fragment ? fragment.getAttribute( 'data-autoslide' ) : null;
			var parentAutoSlide = currentSlide.parentNode ? currentSlide.parentNode.getAttribute( 'data-autoslide' ) : null;
			var slideAutoSlide = currentSlide.getAttribute( 'data-autoslide' );

			// Pick value in the following priority order:
			// 1. Current fragment's data-autoslide
			// 2. Current slide's data-autoslide
			// 3. Parent slide's data-autoslide
			// 4. Global autoSlide setting
			if( fragmentAutoSlide ) {
				autoSlide = parseInt( fragmentAutoSlide, 10 );
			}
			else if( slideAutoSlide ) {
				autoSlide = parseInt( slideAutoSlide, 10 );
			}
			else if( parentAutoSlide ) {
				autoSlide = parseInt( parentAutoSlide, 10 );
			}
			else {
				autoSlide = config.autoSlide;
			}

			// If there are media elements with data-autoplay,
			// automatically set the autoSlide duration to the
			// length of that media. Not applicable if the slide
			// is divided up into fragments.
			// playbackRate is accounted for in the duration.
			if( currentSlide.querySelectorAll( '.fragment' ).length === 0 ) {
				toArray( currentSlide.querySelectorAll( 'video, audio' ) ).forEach( function( el ) {
					if( el.hasAttribute( 'data-autoplay' ) ) {
						if( autoSlide && (el.duration * 1000 / el.playbackRate ) > autoSlide ) {
							autoSlide = ( el.duration * 1000 / el.playbackRate ) + 1000;
						}
					}
				} );
			}

			// Cue the next auto-slide if:
			// - There is an autoSlide value
			// - Auto-sliding isn't paused by the user
			// - The presentation isn't paused
			// - The overview isn't active
			// - The presentation isn't over
			if( autoSlide && !autoSlidePaused && !isPaused() && !isOverview() && ( !Reveal.isLastSlide() || availableFragments().next || config.loop === true ) ) {
				autoSlideTimeout = setTimeout( function() {
					typeof config.autoSlideMethod === 'function' ? config.autoSlideMethod() : navigateNext();
					cueAutoSlide();
				}, autoSlide );
				autoSlideStartTime = Date.now();
			}

			if( autoSlidePlayer ) {
				autoSlidePlayer.setPlaying( autoSlideTimeout !== -1 );
			}

		}

	}