feat(core): new operate addDebugListener for debugging

You can use this operater to debug all the stream of the application

closes #52

packages/core/src/bara.ts

@@ -56,6 +56,25 @@ const bara = (() => {
       app()
       return { appStream, emitterMap, streamRegistry, triggerRegistry }
     },
+    addDebugListener(whichStream: string, callback: (...args: any[]) => void) {
+      const listener = {
+        next: (value: any) => {
+          callback(value)
+        },
+      }
+      if (whichStream === 'app') {
+        appStream.setDebugListener(listener)
+      } else {
+        const stream = streamRegistry.find(s => s.name === whichStream)
+        if (stream) {
+          stream._$.setDebugListener(listener)
+        } else {
+          throw new Error(
+            `[Bara Debugger] Not found any stream registered with name ${whichStream}. You can specify stream 'app' for all stream event.`,
+          )
+        }
+      }
+    },
     useStream<T>(streamSetup: BaraStreamSetup<T>) {
       let stream
       let duplicateIndex = -1
@@ -194,6 +213,7 @@ const bara = (() => {
 })()
 
 const {
+  addDebugListener,
   register,
   useStream,
   useTrigger,
@@ -206,6 +226,7 @@ const {
 } = bara
 
 export {
+  addDebugListener,
   register,
   useStream,
   useTrigger,

packages/core/test/debug.test.ts

@@ -0,0 +1,69 @@
+import {
+  addDebugListener,
+  createEventType,
+  register,
+  useAction,
+  useEvent,
+  useStream,
+  useTrigger,
+} from '../src'
+
+describe('use debugger', () => {
+  it('should attach console log to main app stream', done => {
+    const handler = jest.fn()
+    const handlerReal = jest.fn()
+    const handlerNotFoundStream = jest.fn()
+    const handlerSpecificStream = jest.fn()
+
+    register(() => {
+      const SAMPLE_EVENT = createEventType('SAMPLE_EVENT')
+      const STREAM_ID = 'dev.barajs.debugger'
+      useStream<number>(({ setName, addEventType, emit }) => {
+        setName(STREAM_ID)
+        addEventType(SAMPLE_EVENT)
+
+        let counter = 0
+        const timer = setInterval(() => {
+          emit(SAMPLE_EVENT, counter)
+          counter += 1
+          if (counter > 9) {
+            clearInterval(timer)
+          }
+        }, 500)
+
+        return () => {
+          clearInterval(timer)
+        }
+      })
+
+      // tslint:disable-next-line
+      addDebugListener('app', (data: any) => {
+        handler(data)
+      })
+
+      // Add specific stream debugger by attaching to its name
+      addDebugListener(STREAM_ID, handlerSpecificStream)
+
+      // Add not found stream and expect a handling error
+      expect(() => {
+        addDebugListener(STREAM_ID + '-diff', handlerNotFoundStream)
+      }).toThrow(
+        `[Bara Debugger] Not found any stream registered with name ${STREAM_ID}-diff. You can specify stream 'app' for all stream event.`,
+      )
+
+      useTrigger(() => {
+        const event = useEvent(SAMPLE_EVENT)
+        const action = useAction(handlerReal)
+        return { event, action }
+      })
+    })
+
+    setTimeout(() => {
+      expect(handler).toHaveBeenCalledTimes(9)
+      expect(handlerSpecificStream).toHaveBeenCalledTimes(9)
+      expect(handlerNotFoundStream).not.toHaveBeenCalled()
+      expect(handler).toHaveBeenCalled()
+      done()
+    }, 5000)
+  })
+})