fix(withObs): share props$

src/__tests__/withObs.test.js

@@ -45,6 +45,27 @@ describe('withObs', () => {
     expect(wrapper.find('div').prop('className')).toBe('foo')
   })
 
+  it('should share props$', () => {
+    let count = 0
+
+    const Component = compose(
+      withObs(() => ({
+        props$: Rx.Observable.create((observer) => {
+          count += 1
+          observer.next({})
+        }),
+      })),
+      withObs(({ props$ }) => {
+        props$.subscribe()
+        props$.subscribe()
+        return { props$ }
+      }),
+    )('div')
+
+    mount(<Component />)
+    expect(count).toBe(1)
+  })
+
   it('should be merged with other hoc', () => {
     const Component = compose(
       withObs(() => ({})),

src/utils/shareObservable.js

@@ -0,0 +1,36 @@
+/* eslint-disable import/prefer-default-export */
+import createObservable from './createObservable'
+
+const shareObservable = (observable) => {
+  const observers = []
+  let emitted
+  let lastValue
+
+  observable.subscribe({
+    next: (value) => {
+      emitted = true
+      lastValue = value
+      observers.forEach(o => o.next(value))
+    },
+    complete: value => observers.forEach(o => o.complete(value)),
+    error: error => observers.forEach(o => o.error(error)),
+  })
+
+  return createObservable((observer) => {
+    observers.push(observer)
+
+    if (emitted) {
+      observers.forEach(o => o.next(lastValue))
+    }
+
+    return {
+      unsubscribe: () => {
+        const index = observers.indexOf(observer)
+        if (index === -1) return
+        observers.splice(index, 1)
+      },
+    }
+  })
+}
+
+export default shareObservable

src/withObs.js

@@ -1,5 +1,6 @@
 import callOrUse from './utils/callOrUse'
 import createHOCFromMapper from './utils/createHOCFromMapper'
+import shareObservable from './utils/shareObservable'
 import createHelper from './createHelper'
 
 /**
@@ -20,7 +21,8 @@ import createHelper from './createHelper'
  * }))
  */
 const withObs = obsMapper => createHOCFromMapper((props$, obs) => {
-  const nextObs = callOrUse(obsMapper, { ...obs, props$ })
+  const sharedProps$ = shareObservable(props$)
+  const nextObs = callOrUse(obsMapper, { ...obs, props$: sharedProps$ })
   const { props$: nextProps$ = props$ } = nextObs
   delete nextObs.props$
   return [nextProps$, { ...obs, ...nextObs }]