findAutoAnimateMatches()

in js/controllers/autoanimate.js [554:603]

• 42 lines of code
• 9 McCabe index (conditional complexity)

	findAutoAnimateMatches( pairs, fromScope, toScope, selector, serializer, animationOptions ) {

		let fromMatches = {};
		let toMatches = {};

		[].slice.call( fromScope.querySelectorAll( selector ) ).forEach( ( element, i ) => {
			const key = serializer( element );
			if( typeof key === 'string' && key.length ) {
				fromMatches[key] = fromMatches[key] || [];
				fromMatches[key].push( element );
			}
		} );

		[].slice.call( toScope.querySelectorAll( selector ) ).forEach( ( element, i ) => {
			const key = serializer( element );
			toMatches[key] = toMatches[key] || [];
			toMatches[key].push( element );

			let fromElement;

			// Retrieve the 'from' element
			if( fromMatches[key] ) {
				const primaryIndex = toMatches[key].length - 1;
				const secondaryIndex = fromMatches[key].length - 1;

				// If there are multiple identical from elements, retrieve
				// the one at the same index as our to-element.
				if( fromMatches[key][ primaryIndex ] ) {
					fromElement = fromMatches[key][ primaryIndex ];
					fromMatches[key][ primaryIndex ] = null;
				}
				// If there are no matching from-elements at the same index,
				// use the last one.
				else if( fromMatches[key][ secondaryIndex ] ) {
					fromElement = fromMatches[key][ secondaryIndex ];
					fromMatches[key][ secondaryIndex ] = null;
				}
			}

			// If we've got a matching pair, push it to the list of pairs
			if( fromElement ) {
				pairs.push({
					from: fromElement,
					to: element,
					options: animationOptions
				});
			}
		} );

	}