feat(vest): add state subscription (ealush#606)

packages/vest/src/core/state/__tests__/state.test.js

@@ -88,6 +88,27 @@ describe('state', () => {
       });
     });
   });
+
+  describe('onStateChange', () => {
+    const onStateChange = jest.fn();
+    beforeEach(() => {
+
+      stateRef = state.createRef({
+        keyWithObject: state.registerHandler(() => ({ a: true })),
+      }, onStateChange);
+    });
+
+    it('should run callback on state change', () => {
+      expect(onStateChange).toHaveBeenCalledTimes(1);
+      stateRef.set('key', 'value');
+      expect(onStateChange).toHaveBeenCalledTimes(2);
+    });
+
+    it('should run callback with updated state value', () => {
+      stateRef.set('key', 'value');
+      expect(onStateChange).toHaveBeenCalledWith(stateRef.current(),'key', 'value');
+    });
+  })
 });
 
 const initialState = {

packages/vest/src/core/state/state.js

@@ -38,7 +38,7 @@ export default (function createState() {
     return use;
   }
 
-  function createRef(handlers) {
+  function createRef(handlers, onStateChange) {
     let state = {};
     const registeredHandlers = [];
 
@@ -48,6 +48,9 @@ export default (function createState() {
 
     function set(key, value) {
       state[key] = value;
+      if (isFunction(onStateChange)) {
+        onStateChange(state, key, value);
+      }
     }
 
     function reset() {

packages/vest/src/core/suite/__tests__/__snapshots__/subscribe.test.js.snap

@@ -0,0 +1,24 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`suite.subscribe Should call handler on suite subscription initialization 1`] = `
+Array [
+  Object {
+    "suiteState": Object {
+      "usePending": Object {
+        "lagging": Array [],
+        "pending": Array [],
+      },
+      "useSuiteId": Object {
+        "id": "1",
+        "name": undefined,
+      },
+      "useTestCallbacks": Object {
+        "doneCallbacks": Array [],
+        "fieldCallbacks": Array [],
+      },
+      "useTestObjects": Array [],
+    },
+    "type": "suiteSubscribeInit",
+  },
+]
+`;

packages/vest/src/core/suite/__tests__/subscribe.test.js

@@ -0,0 +1,31 @@
+import vest from 'vest';
+
+describe('suite.subscribe', () => {
+  let suite;
+  let handler;
+  beforeEach(() => {
+    handler = jest.fn();
+    suite = vest.create(() => {
+
+    });
+
+  });
+
+  it('Should call handler on suite subscription initialization', () => {
+
+    suite();
+
+    expect(handler).toHaveBeenCalledTimes(0);
+    suite.subscribe(handler);
+    expect(handler).toHaveBeenCalledTimes(1);
+  });
+
+  it('Should call handler on suite subscription initialization', () => {
+
+    suite();
+
+    suite.subscribe(handler);
+    expect(handler.mock.calls[0]).toMatchSnapshot();
+  });
+
+});

packages/vest/src/core/suite/createSuite.js

@@ -26,11 +26,19 @@ const createSuite = withArgs(args => {
     );
   }
 
+  const handlers = [];
   const stateRef = state.createRef({
     usePending,
     useSuiteId: [useSuiteId, [genId(), name]],
     useTestCallbacks,
     useTestObjects,
+  }, (state, key, value) => {
+    handlers.forEach(fn => fn({
+      key,
+      suiteState: state,
+      type: 'suiteStateUpdate',
+      value
+    }))
   });
 
   /*
@@ -67,6 +75,18 @@ const createSuite = withArgs(args => {
       }
     });
   });
+
+  suite.subscribe = function(handler){
+    if (!isFunction(handler)) return;
+
+    handlers.push(handler);
+
+    handler({
+      type: 'suiteSubscribeInit',
+      suiteState: stateRef.current()
+    });
+  }
+
   return suite;
 });
 

packages/vest/src/typings/vest.d.ts

@@ -162,11 +162,21 @@ interface IOnly {
    */
   group(groupName?: ExclusionArg): void;
 }
+
+interface ISubscribePayload {
+  type: string;
+  suiteState: Record<string, any>;
+  key?: string;
+  value?: any;
+}
+
 interface ICreateResult {
   (...args: any[]): IVestResult;
   get: () => DraftResult;
   reset: () => void;
   remove: (fieldName: string) => void;
+
+  subscribe: (payload: ISubscribePayload) => void;
 }
 
 declare namespace vest {