How to get Facebook friends' email?

Can I get a user's friends emails through Graph API? and How?

Can you find someone Facebook email?

Thankfully, there is another option – you can look for people's profiles by typing in their email address! To do so, simply login to your Facebook profile as normal, and click on the search bar at the very top. Enter the email address of the person you are looking for into the search bar and press enter.

It doesn't appear that you can.

You can get a list of friends, but that only gives you ids and names. It appears you have to get users to give you an access token to pull private info, such as email, on a per user basis.