Links with null values

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [5.0.5] - 2021-07-19
+### Fixed
+- Pagination with null values crashes json parser (#123)
+
 ## [5.0.4] - 2021-05-20
 ### Fixed
 - Missing meta properties in responses
@@ -204,6 +208,7 @@ the Document model.
 ### Added
 - Client: fetch resources, collections, related resources and relationships
 
+[5.0.5]: https://github.com/f3ath/json-api-dart/compare/5.0.4...5.0.5
 [5.0.4]: https://github.com/f3ath/json-api-dart/compare/5.0.3...5.0.4
 [5.0.3]: https://github.com/f3ath/json-api-dart/compare/5.0.2...5.0.3
 [5.0.2]: https://github.com/f3ath/json-api-dart/compare/5.0.1...5.0.2

lib/src/document/inbound_document.dart

@@ -67,9 +67,11 @@ class _Parser {
   Map<String, Object?> meta(Map json) =>
       json.get<Map<String, Object?>>('meta', orGet: () => {});
 
-  Map<String, Link> links(Map json) => json
-      .get<Map>('links', orGet: () => {})
-      .map((k, v) => MapEntry(k.toString(), _link(v)));
+  Map<String, Link> links(Map json) {
+    var links = json.get<Map>('links', orGet: () => {});
+    links.removeWhere((key, value) => value == null);
+    return links.map((k, v) => MapEntry(k.toString(), _link(v)));
+  }
 
   Relationship relationship(Map json) {
     final rel = json.containsKey('data') ? _rel(json['data']) : Relationship();

pubspec.yaml

@@ -1,5 +1,5 @@
 name: json_api
-version: 5.0.4
+version: 5.0.5
 homepage: https://github.com/f3ath/json-api-dart
 description: A framework-agnostic implementations of JSON:API Client and Server. Supports JSON:API v1.0 (https://jsonapi.org)
 environment:

test/unit/document/inbound_document_test.dart

@@ -78,6 +78,14 @@ void main() {
         expect(doc.meta(), isEmpty);
       });
 
+      test('can parse the null link', () {
+        final doc = InboundDocument(payload.nullLink);
+        expect(doc.links()['self'].toString(), 'http://example.com/articles');
+        expect(doc.links()['prev'], isNull);
+        expect(doc.links()['next'], isNull);
+        expect(doc.links()['foobar'], isNull);
+      });
+
       test('can parse primary resource', () {
         final doc = InboundDocument(payload.resource);
         final article = doc.dataAsResource();

test/unit/document/payload.dart

@@ -67,6 +67,15 @@ final example = {
   ]
 };
 
+final nullLink = {
+  'links': {
+    'self': 'http://example.com/articles',
+    'next': null,
+    'last': null,
+  },
+  'data': []
+};
+
 final newResource = {
   'data': {
     'type': 'articles',