function checkCapabilities()

in js/reveal.js [448:482]
21 lines of code
15 McCabe index (conditional complexity)

	function checkCapabilities() {

		isMobileDevice = /(iphone|ipod|ipad|android)/gi.test( UA );
		isChrome = /chrome/i.test( UA ) && !/edge/i.test( UA );

		var testElement = document.createElement( 'div' );

		features.transforms3d = 'WebkitPerspective' in testElement.style ||
								'MozPerspective' in testElement.style ||
								'msPerspective' in testElement.style ||
								'OPerspective' in testElement.style ||
								'perspective' in testElement.style;

		features.transforms2d = 'WebkitTransform' in testElement.style ||
								'MozTransform' in testElement.style ||
								'msTransform' in testElement.style ||
								'OTransform' in testElement.style ||
								'transform' in testElement.style;

		features.requestAnimationFrameMethod = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame;
		features.requestAnimationFrame = typeof features.requestAnimationFrameMethod === 'function';

		features.canvas = !!document.createElement( 'canvas' ).getContext;

		// Transitions in the overview are disabled in desktop and
		// Safari due to lag
		features.overviewTransitions = !/Version\/[\d\.]+.*Safari/.test( UA );

		// Flags if we should use zoom instead of transform to scale
		// up slides. Zoom produces crisper results but has a lot of
		// xbrowser quirks so we only use it in whitelsited browsers.
		features.zoom = 'zoom' in testElement.style && !isMobileDevice &&
						( isChrome || /Version\/[\d\.]+.*Safari/.test( UA ) );

	}