Checking if a steam64 id is your friend?

[QuestionRealQuick1]

Title says it all.

How would i go about checking if a steamid64 is your friend?

am having some crashing issues with my bot attempting to message non friends.

[Revadike]

Assuming you are logged in (user = steam-user instance, steamid = steamid64):
 

function isSteamFriends(steamid) {
    return Object.entries(user.myFriends).filter(e => e[1] === SteamUser.Steam.EFriendRelationship.Friend).map(e => e[0]).includes(steamid);
}