Fix unlike counter, fixes #107

app/controllers/api/v1/statuses/favourites_controller.rb

@@ -19,7 +19,7 @@ class Api::V1::Statuses::FavouritesController < Api::BaseController
 
     UnfavouriteWorker.perform_async(current_user.account_id, @status.id)
 
-    render json: @status, serializer: REST::StatusSerializer, relationships: StatusRelationshipsPresenter.new([@status], current_user&.account_id, favourites_map: @favourites_map)
+    render json: @status, serializer: REST::StatusSerializer, unfavourite: true, relationships: StatusRelationshipsPresenter.new([@status], current_user&.account_id, favourites_map: @favourites_map)
   end
 
   private

app/javascript/gabsocial/reducers/statuses.js

@@ -3,6 +3,7 @@ import {
   REBLOG_FAIL,
   FAVORITE_REQUEST,
   FAVORITE_FAIL,
+  UNFAVORITE_REQUEST,
 } from '../actions/interactions';
 import {
   STATUS_MUTE_SUCCESS,
@@ -39,6 +40,8 @@ export default function statuses(state = initialState, action) {
     return state.setIn([action.status.get('id'), 'favourited'], true);
   case FAVORITE_FAIL:
     return state.get(action.status.get('id')) === undefined ? state : state.setIn([action.status.get('id'), 'favourited'], false);
+  case UNFAVORITE_REQUEST:
+    return state.setIn([action.status.get('id'), 'favourited'], false);
   case REBLOG_REQUEST:
     return state.setIn([action.status.get('id'), 'reblogged'], true);
   case REBLOG_FAIL:

app/serializers/rest/status_serializer.rb

@@ -83,6 +83,16 @@ class REST::StatusSerializer < ActiveModel::Serializer
     end
   end
 
+  def favourites_count
+    if instance_options && instance_options[:unfavourite]
+      # Decrement counter
+      # https://github.com/tootsuite/mastodon/issues/3166
+      object.favourites_count - 1
+    else
+      object.favourites_count
+    end
+  end
+
   def reblogged
     if instance_options && instance_options[:relationships]
       instance_options[:relationships].reblogs_map[object.id] || false