nips/25.md

NIP-25

Reactions

draft optional

A reaction is a kind 7 event that is used to react to other events.

The generic reaction, represented by the content set to a + string, SHOULD be interpreted as a "like" or "upvote".

A reaction with content set to - SHOULD be interpreted as a "dislike" or "downvote". It SHOULD NOT be counted as a "like", and MAY be displayed as a downvote or dislike on a post. A client MAY also choose to tally likes against dislikes in a reddit-like system of upvotes and downvotes, or display them as separate tallies.

The content MAY be an emoji, or NIP-30 custom emoji in this case it MAY be interpreted as a "like" or "dislike", or the client MAY display this emoji reaction on the post. If the content is an empty string then the client should consider it a "+".

Tags

The reaction event SHOULD include e and p tags from the note the user is reacting to (and optionally a tags if the target is a replaceable event). This allows users to be notified of reactions to posts they were mentioned in. Including the e tags enables clients to pull all the reactions associated with individual posts or all the posts in a thread. a tags enables clients to seek reactions for all versions of a replaceable event.

The last e tag MUST be the id of the note that is being reacted to.

The last p tag MUST be the pubkey of the event being reacted to.

The a tag MUST contain the coordinates (kind:pubkey:d-tag) of the replaceable being reacted to.

The reaction event MAY include a k tag with the stringified kind number of the reacted event as its value.

Example code

func make_like_event(pubkey: String, privkey: String, liked: NostrEvent) -> NostrEvent {
    var tags: [[String]] = liked.tags.filter {
    	tag in tag.count >= 2 && (tag[0] == "e" || tag[0] == "p")
    }
    tags.append(["e", liked.id])
    tags.append(["p", liked.pubkey])
    tags.append(["k", liked.kind])
    let ev = NostrEvent(content: "+", pubkey: pubkey, kind: 7, tags: tags)
    ev.calculate_id()
    ev.sign(privkey: privkey)
    return ev
}

Custom Emoji Reaction

The client may specify a custom emoji (NIP-30) :shortcode: in the reaction content. The client should refer to the emoji tag and render the content as an emoji if shortcode is specified.

{
  "kind": 7,
  "content": ":soapbox:",
  "tags": [
    ["emoji", "soapbox", "https://gleasonator.com/emoji/Gleasonator/soapbox.png"]
  ],
  ...other fields
}

The content can be set only one :shortcode:. And emoji tag should be one.

Polling

Authors can request a reaction poll any event kind by using the tag poll. Supporting clients SHOULD present pool options as reaction options, tally and render results as part of the display of the event.

For example:

{
  "kind": 1,
  "content": "Do you folks like pizza?",
  "tags": [
    ["poll", "👍", "👎"]
  ],
  ...other fields
}