Ok so I am making a like/dislike system for my website and I got it to work. The only problem is, is that a user can like something more than once, how do I stop this? heres my function
function thumbup(uid, s) {
const prevthumbs = s.thumbs
firebase.db.collection('users').doc(uid).update({
thumbs: prevthumbs + 1
})
}
How can I limit the increment to only one?
To limit how often the user can do something, use their UID as the key for the operation.
For example, if you don't have too many users, you can have a field likedBy in the document which is an array of the UIDs of the users who liked this user.
It's a bit unclear how to exactly implement it in your code for me, as you're already writing to a doc(uid), where usually the user is liking a post or something like that.