fix: #92 re-sort data after serialization (#93)

.github/workflows/ci.yaml

@@ -54,7 +54,7 @@ jobs:
             node: 18
           - name: macOS
             machine: macos-latest
-            node: 14
+            node: 16
           - name: Windows
             machine: windows-latest
             node: 14

src/classes/polymorphic-serialiser.ts

@@ -66,6 +66,17 @@ export default class PolymorphicSerializer<
         return result;
       }, document);
 
+      // Sort data to match input order - this is important for cases where
+      // data has been sorted prior to serialization.
+      if (Array.isArray(document.data)) {
+        document.data = document.data.sort((a, b) => {
+          const aIndex = data.findIndex((datum) => datum.id === a.id);
+          const bIndex = data.findIndex((datum) => datum.id === b.id);
+
+          return aIndex - bIndex;
+        });
+      }
+
       // Handle meta
       if (options?.metaizers?.document) {
         document.meta = options.metaizers.document.metaize(data);

test/issue-92.test.ts

@@ -0,0 +1,68 @@
+import { PolymorphicSerializer, Serializer } from '../lib';
+import Resource from '../lib/models/resource.model';
+
+describe('Issue #92 - Polymorphic serializer ordering', () => {
+  abstract class Model {
+    public type: string;
+
+    constructor(public id: string) {}
+  }
+
+  class Model1 extends Model {
+    constructor(id: string) {
+      super(id);
+      this.type = 'type:Model1';
+    }
+  }
+
+  class Model2 extends Model {
+    constructor(id: string) {
+      super(id);
+      this.type = 'type:Model2';
+    }
+  }
+
+  it('should maintain data input ordering', async () => {
+    const model1A: Model1 = new Model1('1a');
+    const model1B: Model1 = new Model1('1b');
+    const model1C: Model1 = new Model1('1c');
+    const model2A: Model2 = new Model2('2a');
+    const model2B: Model2 = new Model2('2b');
+
+    const Model1Serializer = new Serializer<Model1>('Model1');
+    const Model2Serializer = new Serializer<Model2>('Model2');
+
+    const PolySerializer = new PolymorphicSerializer<Model>('Model', 'type', {
+      'type:Model1': Model1Serializer,
+      'type:Model2': Model2Serializer,
+    });
+
+    const data = (await PolySerializer.serialize([
+      model1A,
+      model2A,
+      model1C,
+      model2B,
+      model1B,
+    ])) as {
+      data: Resource<Model>;
+    };
+
+    expect(data.data).toBeInstanceOf(Array);
+    expect(data.data).toHaveLength(5);
+
+    expect(data.data[0].id).toEqual('1a');
+    expect(data.data[0].type).toEqual('Model1');
+
+    expect(data.data[1].id).toEqual('2a');
+    expect(data.data[1].type).toEqual('Model2');
+
+    expect(data.data[2].id).toEqual('1c');
+    expect(data.data[2].type).toEqual('Model1');
+
+    expect(data.data[3].id).toEqual('2b');
+    expect(data.data[3].type).toEqual('Model2');
+
+    expect(data.data[4].id).toEqual('1b');
+    expect(data.data[4].type).toEqual('Model1');
+  });
+});