implemented named event handler

src/Database.js

@@ -401,11 +401,11 @@ export default function extendDatabase (Y /* :any */) {
     whenOperationsExist: any;
     */
     * tryExecute (op) {
-      this.store.addToDebug('yield* this.store.tryExecute.call(this, ', JSON.stringify(op), ')')
+      this.store.addToDebug('yield * this.store.tryExecute.call(this, ', JSON.stringify(op), ')')
       if (op.struct === 'Delete') {
         yield * Y.Struct.Delete.execute.call(this, op)
         // this is now called in Transaction.deleteOperation!
-        // yield* this.store.operationAdded(this, op)
+        // yield * this.store.operationAdded(this, op)
       } else {
         // check if this op was defined
         var defined = yield * this.getInsertion(op.id)

src/Transaction.js

@@ -162,14 +162,14 @@ export default function extendTransaction (Y) {
             if (target.start != null) {
               // TODO: don't do it like this .. -.-
               yield * this.deleteList(target.start)
-              // yield* this.deleteList(target.id) -- do not gc itself because this may still get referenced
+              // yield * this.deleteList(target.id) -- do not gc itself because this may still get referenced
             }
             if (target.map != null) {
               for (var name in target.map) {
                 yield * this.deleteList(target.map[name])
               }
               // TODO: here to..  (see above)
-              // yield* this.deleteList(target.id) -- see above
+              // yield * this.deleteList(target.id) -- see above
             }
             if (target.opContent != null) {
               yield * this.deleteOperation(target.opContent)
@@ -223,7 +223,7 @@ export default function extendTransaction (Y) {
     */
     * markGarbageCollected (id, len) {
       // this.mem.push(["gc", id]);
-      this.store.addToDebug('yield* this.markGarbageCollected(', id, ', ', len, ')')
+      this.store.addToDebug('yield * this.markGarbageCollected(', id, ', ', len, ')')
       var n = yield * this.markDeleted(id, len)
       if (n.id[1] < id[1] && !n.gc) {
         // un-extend left
@@ -294,8 +294,9 @@ export default function extendTransaction (Y) {
                 yield * this.ds.put(n)
               } else {
                 // already gc'd
-                throw new Error('Cannot happen! (it dit though.. :()')
-                // return n
+                throw new Error(
+                  'DS reached an inconsistent state. Please report this issue!'
+                )
               }
             }
           } else {
@@ -418,7 +419,7 @@ export default function extendTransaction (Y) {
       * reset origins of all right ops
     */
     * garbageCollectOperation (id) {
-      this.store.addToDebug('yield* this.garbageCollectOperation(', id, ')')
+      this.store.addToDebug('yield * this.garbageCollectOperation(', id, ')')
       var o = yield * this.getOperation(id)
       yield * this.markGarbageCollected(id, (o != null && o.content != null) ? o.content.length : 1) // always mark gc'd
       // if op exists, then clean that mess up..
@@ -475,7 +476,7 @@ export default function extendTransaction (Y) {
             right.origin = neworigin
             // search until you find origin pointer to the left of o
             if (right.right != null) {
-              var i = yield* this.getOperation(right.right)
+              var i = yield * this.getOperation(right.right)
               var ids = [o.id, o.right]
               while (ids.some(function (id) {
                 return Y.utils.compareIds(id, i.origin)
@@ -483,14 +484,14 @@ export default function extendTransaction (Y) {
                 if (Y.utils.compareIds(i.origin, o.id)) {
                   // reset origin of i
                   i.origin = neworigin
-                  yield* this.setOperation(i)
+                  yield * this.setOperation(i)
                 }
                 // get next i
                 if (i.right == null) {
                   break
                 } else {
                   ids.push(i.id)
-                  i = yield* this.getOperation(i.right)
+                  i = yield * this.getOperation(i.right)
                 }
               }
             }
@@ -1086,7 +1087,7 @@ export default function extendTransaction (Y) {
       // or the o that has no origin to the right of op
       // (this is why we use the ids array)
       while (o.right != null) {
-        var right = yield* this.getOperation(o.right)
+        var right = yield * this.getOperation(o.right)
         if (o.right[1] < (startSS[o.right[0]] || 0) || !ids.some(function (id) {
           return Y.utils.compareIds(id, right.origin)
         })) {

src/Utils.js

@@ -42,6 +42,32 @@ export default function Utils (Y) {
     }
   }
 
+  class NamedEventHandler {
+    constructor () {
+      this._eventListener = {}
+    }
+    on (name, f) {
+      if (this._eventListener[name] == null) {
+        this._eventListener[name] = []
+      }
+      this._eventListener[name].push(f)
+    }
+    off (name, f) {
+      if (name == null || f == null) {
+        throw new Error('You must specify event name and function!')
+      }
+      let listener = this._eventListener[name] || []
+      this._eventListener[name] = listener.filter(e => e !== f)
+    }
+    emit (name, value) {
+      (this._eventListener[name] || []).forEach(l => l(value))
+    }
+    destroy () {
+      this._eventListener = null
+    }
+  }
+  Y.utils.NamedEventHandler = NamedEventHandler
+
   class EventListenerHandler {
     constructor () {
       this.eventListeners = []

src/y.js

@@ -144,7 +144,7 @@ export default function Y (opts/* :YOptions */) /* :Promise<YConfig> */ {
   })
 }
 
-class YConfig {
+class YConfig extends Y.utils.NamedEventHandler {
   /* ::
   db: Y.AbstractDatabase;
   connector: Y.AbstractConnector;
@@ -152,6 +152,7 @@ class YConfig {
   options: Object;
   */
   constructor (opts, callback) {
+    super()
     this.options = opts
     this.db = new Y[opts.db.name](this, opts.db)
     this.connector = new Y[opts.connector.name](this, opts.connector)
@@ -215,6 +216,9 @@ class YConfig {
       } else {
         return Promise.resolve()
       }
+    }).then(() => {
+      // remove existing event listener
+      super.destroy()
     })
   }
   close () {