From c817ddd17d03c36eb8288db62276bd7296647b73 Mon Sep 17 00:00:00 2001
From: Will Goto <will@humbledot.com>
Date: Thu, 3 Oct 2019 11:56:17 -0700
Subject: [PATCH 1/2] Create modelDidUpdate method

---
 src/models/Model.js        |  7 +++++++
 tests/models/Model.test.js | 14 ++++++++++++--
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/models/Model.js b/src/models/Model.js
index e691b88..ce72635 100644
--- a/src/models/Model.js
+++ b/src/models/Model.js
@@ -67,6 +67,7 @@ class Model extends Publisher {
 
   setState(nextState) {
     const { prev, next, diff } = this._diffState(nextState);
+    const prevState = { ...this.state };
 
     if (diff) {
       // FOR LOGGING
@@ -76,10 +77,16 @@ class Model extends Publisher {
       // console.groupEnd();
 
       Object.assign(this.state, nextState);
+      this.modelDidUpdate(prevState);
       this.publish();
     }
   }
 
+  modelDidUpdate() {
+    // Template method for invoking behavior after
+    // a model has correctly updated state.
+  }
+
 
   //==================
   // INTERNAL METHODS
diff --git a/tests/models/Model.test.js b/tests/models/Model.test.js
index 76ab4c9..9b0aaf3 100644
--- a/tests/models/Model.test.js
+++ b/tests/models/Model.test.js
@@ -5,7 +5,8 @@ import Model from '../../src/models/Model';
 // TEST CONSTANTS
 //================
 
-const obj = { id: '1' };
+const id = '1';
+const obj = { id };
 const arr = [];
 
 
@@ -41,7 +42,7 @@ describe('Model', () => {
   let modelWithDefaultState;
 
   beforeEach(() => {
-    model = new Test({ id: '1', obj, arr });
+    model = new Test({ id, obj, arr });
     modelWithoutState = new TestWithoutState();
     modelWithDefaultState = new TestWithDefaultState();
   });
@@ -120,6 +121,7 @@ describe('Model', () => {
 
   describe('setState', () => {
     beforeEach(() => {
+      spyOn(model, 'modelDidUpdate');
       spyOn(model, 'publish');
     });
 
@@ -132,6 +134,10 @@ describe('Model', () => {
         expect(model.state.id).toBe('2');
       });
 
+      it('should call modelDidUpdate with the previous state', () => {
+        expect(model.modelDidUpdate).toBeCalledWith({ id, test: true, obj, arr });
+      });
+
       it('should call publish', () => {
         expect(model.publish).toBeCalled();
       });
@@ -147,6 +153,10 @@ describe('Model', () => {
         expect(model.state.obj.id).toBe('2');
       });
 
+      it('should not call modelDidUpdate', () => {
+        expect(model.modelDidUpdate).not.toBeCalled();
+      });
+
       it('should not call publish', () => {
         expect(model.publish).not.toBeCalled();
       });

From db3bf959a1b1806f39b97a58a8b4feb14c1784c3 Mon Sep 17 00:00:00 2001
From: Will Goto <will@humbledot.com>
Date: Thu, 3 Oct 2019 12:03:44 -0700
Subject: [PATCH 2/2] Bump version

---
 package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package.json b/package.json
index 7220598..d6407b4 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "react-axiom",
-  "version": "0.4.0",
+  "version": "0.4.1",
   "description": "React Axiom is a way to use models with React.",
   "repository": "https://github.com/wgoto/react-axiom",
   "main": "lib/index.js",