Fix jsonapi with keyset

gem/lib/pagy/extras/jsonapi.rb

@@ -47,7 +47,7 @@ def pagy_skip_jsonapi?(vars)
       # Override the Backend method
       def pagy_get_page(vars)
         return super if pagy_skip_jsonapi?(vars)
-        return if params[:page].nil?
+        return unless params[:page]
 
         params[:page][vars[:page_param] || DEFAULT[:page_param]]
       end
@@ -61,7 +61,7 @@ module LimitExtraOverride
       # Override the LimitExtra::Backend method
       def pagy_get_limit_param(vars)
         return super if pagy_skip_jsonapi?(vars)
-        return if params[:page].nil?
+        return unless params[:page]
 
         params[:page][vars[:limit_param] || DEFAULT[:limit_param]]
       end
@@ -77,11 +77,8 @@ def pagy_set_query_params(page, vars, query_params)
         return super unless vars[:jsonapi]
 
         query_params['page'] ||= {}
-        query_params['page'][vars[:page_param].to_s]  = page if page
+        query_params['page'][vars[:page_param].to_s]  = page
         query_params['page'][vars[:limit_param].to_s] = vars[:limit] if vars[:limit_extra]
-        # :nocov:
-        query_params.delete(:page) if query_params['page'].empty?
-        # :nocov:
       end
     end
     UrlHelpers.prepend UrlHelperOverride

test/pagy/extras/jsonapi_test.rb.yaml

@@ -1,13 +1,13 @@
 ---
 pagy/extras/jsonapi___pagy_jsonapi_links_(keyset)_test_0002_sets_the_next_value_to_null_when_the_link_is_unavailable:
   :keyset_result:
-    :first: "/foo?page%5Bsize%5D=50"
+    :first: "/foo?page%5Bsize%5D=50&page%5Blatest%5D"
     :last:
     :prev:
     :next:
 pagy/extras/jsonapi___pagy_jsonapi_links_(keyset)_test_0001_returns_the_ordered_links:
   :keyset_result:
-    :first: "/foo?page%5Blatest%5D=eyJpZCI6MTB9&page%5Bsize%5D=10"
+    :first: "/foo?page%5Blatest%5D&page%5Bsize%5D=10"
     :last:
     :prev:
     :next: "/foo?page%5Blatest%5D=eyJpZCI6MjB9&page%5Bsize%5D=10"