code: function handleRenewNowClick( purchase, siteSlug ) {
  	const renewItem = cartItems.getRenewalItemFromProduct( purchase, {
  		domain: purchase.meta,
  	} );
  	const renewItems = [ renewItem ];
  
  	// Track the renew now submit.
  	analytics.tracks.recordEvent( 'calypso_purchases_renew_now_click', {
  		product_slug: purchase.productSlug,
  	} );
  
  	addItems( renewItems );
  
  	page( '/checkout/' + siteSlug );
  }
docs: Adds a purchase renewal to the cart and redirects to checkout.
  
  @param {Object} purchase - the purchase to be renewed
  @param {string} siteSlug - the site slug to renew the purchase for