feat(store,storeconfig): config for deepFreeze function

Adds deepFreezeFunction in StoreConfigOptions and unit tests for feature
Can use custom deepFreeze for complex objects in store

Resolves salesforce#124

akita/__tests__/deepFreeze.spec.ts

@@ -0,0 +1,79 @@
+import { Store } from '../src/store';
+import { StoreConfig } from '../src/storeConfig';
+import { deepFreeze } from '../src/deepFreeze';
+
+class SpecialObject {
+  specialString: string = 'special';
+  specialNumber: number = 2;
+
+  constructor(params: Partial<ComplexState>) {
+    Object.assign(this, params);
+  }
+}
+
+class ComplexState {
+  propertyString: string = '';
+  propertyNumber: number = 1;
+  specialObject: SpecialObject = new SpecialObject({});
+
+  constructor(params: Partial<ComplexState>) {
+    Object.assign(this, params);
+  }
+}
+
+@StoreConfig({
+  name: 'complexState'
+})
+class ComplexStore extends Store<ComplexState> {
+  constructor() {
+    super(new ComplexState({}));
+  }
+}
+
+const complexStore = new ComplexStore();
+
+describe('store with no custom deepFreeze', () => {
+  it('should use default function', () => {
+    expect(complexStore.deepFreeze).toEqual(deepFreeze);
+  });
+
+  it('should freeze all properties', () => {
+    expect(Object.isFrozen(complexStore._value().propertyNumber)).toBeTruthy();
+    expect(Object.isFrozen(complexStore._value().propertyString)).toBeTruthy();
+    expect(Object.isFrozen(complexStore._value().specialObject)).toBeTruthy();
+    expect(Object.isFrozen(complexStore._value().specialObject.specialNumber)).toBeTruthy();
+    expect(Object.isFrozen(complexStore._value().specialObject.specialString)).toBeTruthy();
+  });
+});
+
+function deepFreezeCustom(o: ComplexState) {
+  Object.freeze(o);
+
+  return o;
+}
+
+@StoreConfig({
+  name: 'complexState2',
+  deepFreezeFunction: deepFreezeCustom
+})
+class ComplexStoreCustom extends Store<ComplexState> {
+  constructor() {
+    super(new ComplexState({}));
+  }
+}
+
+const complexStoreCustom = new ComplexStoreCustom();
+
+describe('store with custom deepFreeze', () => {
+  it('should use custom function', () => {
+    expect(complexStoreCustom.deepFreeze).toEqual(deepFreezeCustom);
+  });
+
+  it('should not freeze all properties', () => {
+    expect(Object.isFrozen(complexStoreCustom._value().propertyNumber)).toBeTruthy();
+    expect(Object.isFrozen(complexStoreCustom._value().propertyString)).toBeTruthy();
+    expect(Object.isFrozen(complexStoreCustom._value().specialObject)).toBeFalsy();
+    expect(Object.isFrozen(complexStoreCustom._value().specialObject.specialNumber)).toBeTruthy();
+    expect(Object.isFrozen(complexStoreCustom._value().specialObject.specialString)).toBeTruthy();
+  });
+});

akita/src/store.ts

@@ -133,14 +133,19 @@ export class Store<S> {
     return this.config.idKey || this.options.idKey || DEFAULT_ID_KEY;
   }
 
+  // @internal
+  get deepFreeze() {
+    return this.config.deepFreezeFunction || this.options.deepFreezeFunction || deepFreeze;
+  }
+
   // @internal
   get cacheConfig() {
     return this.config.cache || this.options.cache;
   }
 
   // @internal
   _setState(newStateFn: (state: Readonly<S>) => S, _dispatchAction = true) {
-    this.storeValue = __DEV__ ? deepFreeze(newStateFn(this._value())) : newStateFn(this._value());
+    this.storeValue = __DEV__ ? this.deepFreeze(newStateFn(this._value())) : newStateFn(this._value());
 
     if (!this.store) {
       this.store = new BehaviorSubject(this.storeValue);

akita/src/storeConfig.ts

@@ -4,6 +4,7 @@ export type StoreConfigOptions = {
   idKey?: string;
   storeName?: string;
   cache?: { ttl: number };
+  deepFreezeFunction?: (o: any) => any;
 };
 
 export type UpdatableStoreConfigOptions = {