feat(@tinacms/events): EventBus#subscribe can accept an array of even…

…t names

packages/@tinacms/core/src/event.ts

@@ -25,13 +25,21 @@ export interface CMSEvent {
 export class EventBus {
   private listeners = new Set<Listener>()
 
-  subscribe = (event: string, callback: Callback): (() => void) => {
-    const listener = new Listener(event, callback)
+  subscribe = (event: string | string[], callback: Callback): (() => void) => {
+    let events: string[]
 
-    this.listeners.add(listener)
+    if (typeof event === 'string') {
+      events = [event]
+    } else {
+      events = event
+    }
+
+    const newListeners = events.map(event => new Listener(event, callback))
+
+    newListeners.forEach(newListener => this.listeners.add(newListener))
 
     return () => {
-      this.listeners.delete(listener)
+      newListeners.forEach(listener => this.listeners.delete(listener))
     }
   }
 

packages/@tinacms/core/src/events.test.ts

@@ -29,6 +29,19 @@ describe('EventBus', () => {
 
     expect(listener).toHaveBeenCalledWith(event)
   })
+  test('for an array of eventscalls listeners and passes it the dispatched event', () => {
+    const listener = jest.fn()
+    const events = new EventBus()
+    const one = { type: 'one' }
+    const two = { type: 'two' }
+
+    events.subscribe(['one', 'two'], listener)
+    events.dispatch(one)
+    events.dispatch(two)
+
+    expect(listener).toHaveBeenCalledWith(two)
+    expect(listener).toHaveBeenCalledWith(one)
+  })
   describe('after calling unsubscribe', () => {
     it('does not invoke the listener', () => {
       const listener = jest.fn()