Use JS SDK to save payment methods (for future during-purchase transactions)

You can use the PayPal JavaScript SDK to save a payer’s payment method and use it for future checkout transactions.    

If your Checkout integration is a client and server-side integration, using the JS SDK you can,

• Save credit and debit cards. 
• Save PayPal wallets. 
• Save Venmo details.

If your Checkout integration is client-side, using the JS SDK, you can save the payers' PayPal wallets .