Function createCache

src/selector/createCache.js:9–24

()

 *	deleting the oldest entry
 */
export function createCache() {
	var keys = [];

	function cache( key, value ) {

		// Use (key + " ") to avoid collision with native prototype properties
		// (see https://github.com/jquery/sizzle/issues/157)
		if ( keys.push( key + " " ) > jQuery.expr.cacheLength ) {

			// Only keep the most recent entries
			delete cache[ keys.shift() ];
		}
		return ( cache[ key + " " ] = value );
	}
	return cache;
}