Created event compaction.done fired by datastore after a compaction o…

…peration is complete

lib/datastore.js

@@ -22,6 +22,9 @@ var customUtils = require('./customUtils')
  * @param {Function} options.afterSerialization/options.beforeDeserialization Optional, serialization hooks
  * @param {Number} options.corruptAlertThreshold Optional, threshold after which an alert is thrown if too much data is corrupt
  * @param {Function} options.compareStrings Optional, string comparison function that overrides default for sorting
+ *
+ * Event Emitter - Events
+ * * compaction.done - Fired whenever a compaction operation was finished
  */
 function Datastore (options) {
   var filename;
@@ -74,6 +77,8 @@ function Datastore (options) {
   }); }
 }
 
+util.inherits(Datastore, require('events'));
+
 
 /**
  * Load the database from the datafile, and trigger the execution of buffered commands if any

lib/persistence.js

@@ -134,7 +134,11 @@ Persistence.prototype.persistCachedDatabase = function (cb) {
     }
   });
 
-  storage.crashSafeWriteFile(this.filename, toPersist, callback);
+  storage.crashSafeWriteFile(this.filename, toPersist, function (err) {
+    if (err) { return callback(err); }
+    self.db.emit('compaction.done');
+    return callback(null);
+  });
 };
 
 

test/persistence.test.js

@@ -144,7 +144,7 @@ describe('Persistence', function () {
     treatedData.length.should.equal(2);
     _.isEqual(treatedData[0], { _id: "1", a: 2, ages: [1, 5, 12] }).should.equal(true);
     _.isEqual(treatedData[1], { _id: "3", today: now }).should.equal(true);
-  });  
+  });
 
   it('Compact database on load', function (done) {
     d.insert({ a: 2 }, function () {
@@ -299,6 +299,15 @@ describe('Persistence', function () {
     });
   });
 
+  it("Can listen to compaction events", function (done) {
+    d.on('compaction.done', function () {
+      d.removeAllListeners('compaction.done');   // Tidy up for next tests
+      done();
+    });
+
+    d.persistence.compactDatafile();
+  });
+
 
   describe('Serialization hooks', function () {
     var as = function (s) { return "before_" + s + "_after"; }