function activateOverview()

in js/reveal.js [1752:1797]
18 lines of code
5 McCabe index (conditional complexity)

	function activateOverview() {

		// Only proceed if enabled in config
		if( config.overview && !isOverview() ) {

			overview = true;

			dom.wrapper.classList.add( 'overview' );
			dom.wrapper.classList.remove( 'overview-deactivating' );

			if( features.overviewTransitions ) {
				setTimeout( function() {
					dom.wrapper.classList.add( 'overview-animated' );
				}, 1 );
			}

			// Don't auto-slide while in overview mode
			cancelAutoSlide();

			// Move the backgrounds element into the slide container to
			// that the same scaling is applied
			dom.slides.appendChild( dom.background );

			// Clicking on an overview slide navigates to it
			toArray( dom.wrapper.querySelectorAll( SLIDES_SELECTOR ) ).forEach( function( slide ) {
				if( !slide.classList.contains( 'stack' ) ) {
					slide.addEventListener( 'click', onOverviewSlideClicked, true );
				}
			} );

			updateSlidesVisibility();
			layoutOverview();
			updateOverview();

			layout();

			// Notify observers of the overview showing
			dispatchEvent( 'overviewshown', {
				'indexh': indexh,
				'indexv': indexv,
				'currentSlide': currentSlide
			} );

		}

	}