Added aggregate diff event

* Provide a single event  for all changes from a binlog event

Author: numtel

README.md

@@ -5,6 +5,7 @@ NPM Package to provide events when a MySQL select statement result set changes.
 Built using the [`zongji` Binlog Tailer](https://github.com/nevill/zongji) and [`node-mysql`](https://github.com/felixge/node-mysql) projects.
 
 * [Example Application using Express, SockJS and React](https://github.com/numtel/reactive-mysql-example)
+* [Meteor package for reactive MySQL](https://github.com/numtel/meteor-mysql)
 
 ## Installation
 
@@ -121,6 +122,7 @@ Event Name | Arguments | Description
 `added` | `row`, `index` | Row added to result set at index
 `changed` | `row`, `newRow`, `index` | Row contents mutated at index
 `removed` | `row`, `index` | Row removed at index
+`diff` | `diff` | Aggregation of `added`, `changed`, `removed` events for current event into a single array for easier handling of multiple changes
 `error` | `error` | Unhandled errors will be thrown
 
 ## Running Tests

lib/LiveMysqlSelect.js

@@ -75,21 +75,30 @@ LiveMysqlSelect.prototype._setRows = function(rows){
   self.emit('update', rows);
 
   if(!self.base.settings.skipDiff){
+    var diff = [];
+    var diffEvent = function(){
+      self.emit.apply(self, arguments);
+      diff.push(Array.prototype.slice.call(arguments));
+    }
     rows.forEach(function(row, index){
       if(self.data.length - 1 < index){
-        self.emit('added', row, index);
+        diffEvent('added', row, index);
         self.data[index] = row;
       }else if(JSON.stringify(self.data[index]) !== JSON.stringify(row)){
-        self.emit('changed', self.data[index], row, index);
+        diffEvent('changed', self.data[index], row, index);
         self.data[index] = row;
       }
     });
     if(self.data.length > rows.length){
       for(var i = self.data.length - 1; i >= rows.length; i--){
-        self.emit('removed', self.data[i], i);
+        diffEvent('removed', self.data[i], i);
       }
       self.data.splice(rows.length, self.data.length - rows.length);
     }
+    if(diff.length !== 0){
+      // Output all difference events in a single event
+      self.emit('diff', diff);
+    }
   }
 
   self.lastUpdate = Date.now();

package.json

@@ -1,6 +1,6 @@
 {
   "name": "mysql-live-select",
-  "version": "0.0.8",
+  "version": "0.0.9",
   "description": "Live updating MySQL SELECT statements",
   "main": "lib/LiveMysql.js",
   "repository": "https://github.com/numtel/mysql-live-select",

test/index.js

@@ -47,6 +47,23 @@ module.exports = {
             }).on('removed', function(row, index){
               test.equal(index, 0);
               test.equal(row.col, 15);
+            }).on('diff', function(diff){
+              // Only one row will change at once
+              test.equal(diff.length, 1);
+              // Index will always be 0, the first item
+              test.equal(diff[0][diff[0].length - 1], 0);
+              switch(diff[0][0]){
+                case 'added':
+                  test.equal(diff[0][1].col, 10);
+                  break;
+                case 'changed':
+                  test.equal(diff[0][1].col, 10);
+                  test.equal(diff[0][2].col, 15);
+                  break;
+                case 'added':
+                  test.equal(diff[0][1].col, 15);
+                  break;
+              }
             });
 
             querySequence(conn.db, [