function cueAutoSlide()

in js/reveal.js [2200:2270]
45 lines of code
21 McCabe index (conditional complexity)

	function cueAutoSlide() {

		cancelAutoSlide();

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

			let fragment = currentSlide.querySelector( '.current-fragment[data-autoslide]' );

			let fragmentAutoSlide = fragment ? fragment.getAttribute( 'data-autoslide' ) : null;
			let parentAutoSlide = currentSlide.parentNode ? currentSlide.parentNode.getAttribute( 'data-autoslide' ) : null;
			let 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 ) {
					Util.queryAll( currentSlide, 'video, audio' ).forEach( 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() && !overview.isActive() && ( !isLastSlide() || fragments.availableRoutes().next || config.loop === true ) ) {
				autoSlideTimeout = setTimeout( () => {
					if( typeof config.autoSlideMethod === 'function' ) {
						config.autoSlideMethod()
					}
					else {
						navigateNext();
					}
					cueAutoSlide();
				}, autoSlide );
				autoSlideStartTime = Date.now();
			}

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

		}

	}