From 47f0731df603ed9bbb6e288e1089404427742f9d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Aur=C3=A9lien=20Georget?= <aurelsicoko@gmail.com>
Date: Mon, 7 Mar 2016 18:34:27 +0100
Subject: [PATCH] Improve JSON API pagination

---
 .../hooks/jsonapi/helpers/response.js         | 28 ++++++++++++++-----
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/lib/configuration/hooks/jsonapi/helpers/response.js b/lib/configuration/hooks/jsonapi/helpers/response.js
index 6fc59f4a05..17c0f374f7 100644
--- a/lib/configuration/hooks/jsonapi/helpers/response.js
+++ b/lib/configuration/hooks/jsonapi/helpers/response.js
@@ -46,7 +46,7 @@ module.exports = {
     // Fetch and format value
     const value = this.fetchValue(ctx, object);
 
-    if (!_.isEmpty(value)) {
+    if (!_.isNull(value)) {
       ctx.response.body = yield this.serialize(ctx, type, object, value, matchedRoute);
     }
   },
@@ -160,7 +160,7 @@ module.exports = {
 
           // Get current page number
           const value = _.first(_.values(_.pick(ctx.state.query, 'page[number]')));
-          const currentPage = _.isEmpty(value) ? 1 : value;
+          const currentPage = _.isEmpty(value) || parseInt(value, 10) === 0 ? 1 : value;
 
           // Verify integer
           if (currentPage.toString() === parseInt(currentPage, 10).toString()) {
@@ -169,17 +169,31 @@ module.exports = {
             links.next = ctx.request.origin + ctx.state.url + '?page[number]=' + (parseInt(currentPage, 10) + 1);
             links.last = ctx.request.origin + ctx.state.url + '?page[number]=' + pageNumber;
 
+            // Second page
             if ((parseInt(currentPage, 10) - 1) === 0) {
               links.prev = links.first;
             }
 
+            // Before last page
+            if ((parseInt(currentPage, 10) - 1) === pageNumber) {
+              links.next = links.last;
+            }
+
+            // No data
+            if (pageNumber === 0) {
+              links.prev = null;
+              links.next = null;
+              links.last = null;
+            }
+
             // Last page
-            if (ctx.request.url === ctx.state.url + '?page[number]=' + pageNumber) {
-              // Don't display useless
+            if (parseInt(currentPage, 10) === pageNumber) {
               links.last = null;
               links.next = null;
-            } else if (ctx.request.url === ctx.state.url) {
-              // First page
+            }
+
+            // First page
+            if (parseInt(currentPage, 10) === 1) {
               links.first = null;
               links.prev = null;
             }
@@ -295,7 +309,7 @@ module.exports = {
    */
 
   fetchValue: function (ctx, object) {
-    const data = ctx.body.toJSON() || ctx.body;
+    const data = _.isFunction(_.get(ctx.body, 'toJSON')) ? ctx.body.toJSON() : ctx.body;
 
     switch (object) {
       case 'collection':