updateRelationship replaces relations

addon/mixins/resource-operations.js

@@ -96,7 +96,7 @@ export default Ember.Mixin.create({
 
   /**
     Update a relationship, works with both `to-many` and `to-one`. Primarily use
-    with `to-one` as `to-many` is for a full replacement only.
+    with `to-one` and `to-many` is for a full replacement only.
 
     For a `to-one` relationship, add, replace or remove, and persist the change
     using the service. With an id the relation will be added or changed, with
@@ -105,7 +105,8 @@ export default Ember.Mixin.create({
     See: <http://jsonapi.org/format/#crud-updating-resource-relationships>
 
     For `to-many` relationships the backend will need to support editing as a set,
-    full replacement (most often that may be disabled).
+    full replacement (most often that may be disabled). The list of all related
+    resource identifiers will be sent to the server as a replace operation.
 
     Update a relationship by adding or removing using a list, id, or null. When
     adding an id for a to-many relationship send one or more ids, include the
@@ -132,7 +133,7 @@ export default Ember.Mixin.create({
     } else if (related.kind === 'toMany') {
       rollback = related.mapBy('id');
     }
-    this._updateRelationshipsData(relationship, ids);
+    this._replaceRelationshipsData(relationship, ids);
     return this.get('service').patchRelationship(this, relationship)
     .catch(function (error) {
       this._updateRelationshipsData(relationship, rollback);

addon/models/resource.js

@@ -138,18 +138,10 @@ const Resource = Ember.Object.extend(ResourceOperationsMixin, {
     @param {Array|String|null} ids
   */
   _updateRelationshipsData(relation, ids) {
-    let relationshipData = 'relationships.' + relation + '.data';
-    let existing;
     if (!Array.isArray(ids)) {
-      existing = this.get(relationshipData).id;
-      if (ids === null || isType('string', ids) && existing !== ids) {
-        this.removeRelationship(relation, existing);
-        if (ids !== null) {
-          this.addRelationship(relation, ids);
-        }
-      }
+      this._updateToOneRelationshipData(relation, ids); 
     } else {
-      existing = this.get(relationshipData).map(function(rel) { return rel.id; });
+      let existing = this._existingRelationshipData(relation);
       if (!existing.length) {
         this.addRelationships(relation, ids);
       } else if (ids.length > existing.length) {
@@ -160,6 +152,54 @@ const Resource = Ember.Object.extend(ResourceOperationsMixin, {
     }
   },
 
+  /**
+    @private
+    @method _updateToOneRelationshipData
+    @param {String} relation
+    @param {String|null} id
+  */
+  _updateToOneRelationshipData(relation, id) {
+    let relationshipData = 'relationships.' + relation + '.data';
+    let existing = this.get(relationshipData);
+    existing = (existing) ? existing.id : null;
+    if (id === null || isType('string', id) && existing !== id) {
+      this.removeRelationship(relation, existing);
+      if (id !== null) {
+        this.addRelationship(relation, id);
+      }
+    }
+  },
+
+  /**
+    @private
+    @method _replaceRelationshipsData
+    @param {String} relation
+    @param {Array|String|null} ids
+  */
+  _replaceRelationshipsData(relation, ids) {
+    if (!Array.isArray(ids)) {
+      this._updateToOneRelationshipData(relation, ids); 
+    } else {
+      let existing = this._existingRelationshipData(relation);
+      if (!existing.length) {
+        this.addRelationships(relation, ids);
+      } else {
+        this.removeRelationships(relation, existing);
+        this.addRelationships(relation, ids);
+      }
+    }
+  },
+
+  /**
+    @private
+    @method _existingRelationshipData
+    @param {String} relation
+  */
+  _existingRelationshipData(relation) {
+    let relationshipData = 'relationships.' + relation + '.data';
+    return this.get(relationshipData).map(function(rel) { return rel.id; });
+  },
+
   /**
     @method addRelationships
     @param {String} related - resource name

tests/unit/mixins/resource-operations-test.js

@@ -30,8 +30,8 @@ module('Unit | Mixin | resource-operations', {
     this.subject = Cowboy.create({ id: 1, name:'Lone Ranger'});
     // mock payload setup
     this.subject.set('relationships', {
-      guns: { links: { related: 'url' } },
-      horse: { links: { related: 'url' } }
+      guns: { links: { related: 'url' }, data: [] },
+      horse: { links: { related: 'url' }, data: null }
     });
   },
   afterEach() {
@@ -115,13 +115,13 @@ test('deleteRelationship for to-many relation', function(assert) {
 
 
 test('updateRelationship for to-one relation', function(assert) {
-  this.sandbox.stub(this.subject, '_updateRelationshipsData');
+  this.sandbox.stub(this.subject, '_replaceRelationshipsData');
 
   let promise = this.subject.updateRelationship('horse', 1);
   assert.ok(typeof promise.then === 'function', 'returns a thenable');
   assert.ok(
-    this.subject._updateRelationshipsData.calledWith('horse', 1),
-    'called _updateRelationshipsData'
+    this.subject._replaceRelationshipsData.calledWith('horse', 1),
+    'called _replaceRelationshipsData'
   );
 
   let args = this.subject.get('service').patchRelationship.firstCall.args;

tests/unit/models/resource-test.js

@@ -613,24 +613,41 @@ test('#updateRelationship, from resource-operations mixin', function(assert) {
   });
   let author = post.get('relationships.author.data');
   let comments = post.get('relationships.comments.data');
+  let commentsIds = comments.map(comment => comment.id).sort();
   assert.equal(author.id, 2, 'post has author id 2');
+  assert.deepEqual(commentsIds, ['4'], 'post has comments with id 4');
 
   post.updateRelationship('comments', ['4', '5']);
   comments = post.get('relationships.comments.data');
+  commentsIds = comments.map(comment => comment.id).sort();
   assert.ok(serviceOp.calledOnce, 'service#patchRelationship called once');
   assert.equal(comments.length, 2, 'post has 2 comments');
+  assert.deepEqual(commentsIds, ['4', '5'], 'post has comments with id 4 and 5');
+
+  post.updateRelationship('comments', ['2', '5']);
+  comments = post.get('relationships.comments.data');
+  commentsIds = comments.map(comment => comment.id).sort();
+  assert.ok(serviceOp.calledTwice, 'service#patchRelationship called once');
+  assert.deepEqual(comments.length, 2, 'post has 2 comments');
+  assert.deepEqual(commentsIds, ['2', '5'], 'post has comments with id 2 and 5');
 
   post.updateRelationship('comments', ['1', '2', '3', '4']);
   comments = post.get('relationships.comments.data');
-  assert.equal(comments.length, 5, 'post has 5 comments');
+  commentsIds = comments.map(comment => comment.id).sort();
+  assert.equal(comments.length, 4, 'post has 4 comments');
+  assert.deepEqual(commentsIds, ['1', '2', '3', '4'], 'post has comments with id 1, 2, 3 and 4');
 
   post.updateRelationship('comments', ['1', '2']);
   comments = post.get('relationships.comments.data');
+  commentsIds = comments.map(comment => comment.id).sort();
   assert.equal(comments.length, 2, 'post has 2 comments');
+  assert.deepEqual(commentsIds, ['1', '2'], 'post has comments with id 1 and 2');
 
   post.updateRelationship('comments', []);
   comments = post.get('relationships.comments.data');
+  commentsIds = comments.map(comment => comment.id).sort();
   assert.equal(comments.length, 0, 'post has 0 comments');
+  assert.deepEqual(commentsIds, [], 'post has not comments');
 
   post.updateRelationship('author', '1');
   author = post.get('relationships.author.data');