[FEATURE ds-serialize-id] add serializeId to json-serializer

FEATURES.md

@@ -130,3 +130,19 @@ entry in `config/features.json`.
     tom.resetAttribute('lastName')  // { firstName: 'Tom', lastName: 'Dale' }
     tom.get('hasDirtyAttributes')   // false
   ```
+
+- `ds-serialize-id` [#4620](https://github.com/emberjs/data/pull/4620)
+
+  Adds a `serializeId` method to JSONSerializer. 
+
+  ```js
+   // app/serializers/application.js
+   import DS from 'ember-data';
+
+   export default DS.JSONSerializer.extend({
+     serializeId(snapshot, json, primaryKey) {
+       var id = snapshot.id;
+       json[primaryKey] = parseInt(id, 10);
+     }
+   });
+  ```

addon/serializers/json.js

@@ -1050,10 +1050,13 @@ var JSONSerializer = Serializer.extend({
     var json = {};
 
     if (options && options.includeId) {
-      var id = snapshot.id;
-
-      if (id) {
-        json[get(this, 'primaryKey')] = id;
+      if (isEnabled('ds-serialize-id')) {
+        this.serializeId(snapshot, json, get(this, 'primaryKey'));
+      } else {
+        var id = snapshot.id;
+        if (id) {
+          json[get(this, 'primaryKey')] = id;
+        }
       }
     }
 
@@ -1535,4 +1538,41 @@ if (isEnabled("ds-payload-type-hooks")) {
 
 }
 
+if (isEnabled("ds-serialize-id")) {
+
+  JSONSerializer.reopen({
+
+    /**
+     serializeId can be used to customize how id is serialized
+     For example, your server may expect integer datatype of id
+
+     By default the snapshot's id (String) is set on the json hash via json[primaryKey] = snapshot.id.
+
+     ```app/serializers/application.js
+     import DS from 'ember-data';
+
+     export default DS.JSONSerializer.extend({
+     serializeId(snapshot, json, primaryKey) {
+         var id = snapshot.id;
+         json[primaryKey] = parseInt(id, 10);
+       }
+     });
+     ```
+
+     @method serializeId
+     @public
+     @param {DS.Snapshot} snapshot
+     @param {Object} json
+     @param {String} primaryKey
+     */
+    serializeId(snapshot, json, primaryKey) {
+      var id = snapshot.id;
+
+      if (id) {
+        json[primaryKey] = id;
+      }
+    }
+  });
+}
+
 export default JSONSerializer;

config/features.json

@@ -5,5 +5,6 @@
   "ds-overhaul-references": null,
   "ds-payload-type-hooks": null,
   "ds-check-should-serialize-relationships": null,
-  "ds-reset-attribute": null
+  "ds-reset-attribute": null,
+  "ds-serialize-id": null
 }

tests/integration/serializers/json-serializer-test.js

@@ -68,6 +68,66 @@ test("serialize includes id when includeId is true", function(assert) {
   });
 });
 
+if (isEnabled("ds-serialize-id")) {
+  test("serializeId", function(assert) {
+    run(function() {
+      post = env.store.createRecord('post');
+      post.set('id', 'test');
+    });
+    var json = {};
+
+    env.serializer.serializeId(post._createSnapshot(), json, 'id');
+
+    assert.deepEqual(json, {
+      id: 'test'
+    });
+  });
+
+  test("modified serializeId is called from serialize", function(assert) {
+    env.registry.register('serializer:post', DS.JSONSerializer.extend({
+      serializeId(snapshot, json, primaryKey) {
+        var id = snapshot.id;
+        json[primaryKey] = id.toUpperCase();
+      }
+    }));
+
+    run(function() {
+      post = env.store.createRecord('post', { title: 'Rails is omakase' });
+      post.set('id', 'test');
+    });
+    var json = {};
+
+    json = env.store.serializerFor("post").serialize(post._createSnapshot(), { includeId: true });
+
+    assert.deepEqual(json, {
+      id: 'TEST',
+      title: 'Rails is omakase',
+      comments: []
+    });
+  });
+
+  test("serializeId respects `primaryKey` serializer property", function(assert) {
+    env.registry.register('serializer:post', DS.JSONSerializer.extend({
+      primaryKey: '_ID_'
+    }));
+
+    run(function() {
+      post = env.store.createRecord('post', {  title: 'Rails is omakase' });
+      post.set('id', 'test');
+    });
+    var json = {};
+
+    json = env.store.serializerFor("post").serialize(post._createSnapshot(), { includeId: true });
+
+    assert.deepEqual(json, {
+      _ID_: 'test',
+      title: 'Rails is omakase',
+      comments: []
+    });
+  });
+
+}
+
 test("serializeAttribute", function(assert) {
   run(function() {
     post = env.store.createRecord('post', { title: "Rails is omakase" });