0.0.11: Update event on empty initial result set

Related to numtel/meteor-pg#4

Author: numtel

lib/LivePG.js

@@ -284,7 +284,8 @@ var LivePG = (function (_EventEmitter) {
               triggers: triggers,
               data: [],
               handlers: [handle],
-              notifications: []
+              notifications: [],
+              initialized: false
             };
             context$2$0.next = 11;
             return common.getClient(this.connStr);
@@ -411,7 +412,7 @@ var LivePG = (function (_EventEmitter) {
   }, {
     key: '_updateQuery',
     value: function _updateQuery(queryHash) {
-      var pgHandle, queryBuffer, update, _iteratorNormalCompletion4, _didIteratorError4, _iteratorError4, _iterator4, _step4, updateHandler;
+      var pgHandle, queryBuffer, update, _iteratorNormalCompletion4, _didIteratorError4, _iteratorError4, _iterator4, _step4, updateHandler, _iteratorNormalCompletion5, _didIteratorError5, _iteratorError5, _iterator5, _step5;
 
       return _regeneratorRuntime.async(function _updateQuery$(context$2$0) {
         while (1) switch (context$2$0.prev = context$2$0.next) {
@@ -431,7 +432,7 @@ var LivePG = (function (_EventEmitter) {
             pgHandle.done();
 
             if (!(update !== null)) {
-              context$2$0.next = 29;
+              context$2$0.next = 31;
               break;
             }
 
@@ -480,10 +481,68 @@ var LivePG = (function (_EventEmitter) {
             return context$2$0.finish(21);
 
           case 29:
+            context$2$0.next = 51;
+            break;
+
+          case 31:
+            if (!(queryBuffer.initialized === false)) {
+              context$2$0.next = 51;
+              break;
+            }
+
+            _iteratorNormalCompletion5 = true;
+            _didIteratorError5 = false;
+            _iteratorError5 = undefined;
+            context$2$0.prev = 35;
+
+            // Initial update with empty data
+            for (_iterator5 = _getIterator(queryBuffer.handlers); !(_iteratorNormalCompletion5 = (_step5 = _iterator5.next()).done); _iteratorNormalCompletion5 = true) {
+              updateHandler = _step5.value;
+
+              updateHandler.emit('update', { removed: null, moved: null, copied: null, added: [] }, []);
+            }
+            context$2$0.next = 43;
+            break;
+
+          case 39:
+            context$2$0.prev = 39;
+            context$2$0.t4 = context$2$0['catch'](35);
+            _didIteratorError5 = true;
+            _iteratorError5 = context$2$0.t4;
+
+          case 43:
+            context$2$0.prev = 43;
+            context$2$0.prev = 44;
+
+            if (!_iteratorNormalCompletion5 && _iterator5['return']) {
+              _iterator5['return']();
+            }
+
+          case 46:
+            context$2$0.prev = 46;
+
+            if (!_didIteratorError5) {
+              context$2$0.next = 49;
+              break;
+            }
+
+            throw _iteratorError5;
+
+          case 49:
+            return context$2$0.finish(46);
+
+          case 50:
+            return context$2$0.finish(43);
+
+          case 51:
+
+            queryBuffer.initialized = true;
+
+          case 52:
           case 'end':
             return context$2$0.stop();
         }
-      }, null, this, [[13, 17, 21, 29], [22,, 24, 28]]);
+      }, null, this, [[13, 17, 21, 29], [22,, 24, 28], [35, 39, 43, 51], [44,, 46, 50]]);
     }
   }, {
     key: '_processNotification',

package.json

@@ -1,6 +1,6 @@
 {
   "name"        : "pg-live-select",
-  "version"     : "0.0.10",
+  "version"     : "0.0.11",
   "description" : "Live updating PostgreSQL SELECT statements",
   "main"        : "lib/LivePG.js",
   "license"     : "MIT",

src/LivePG.es6

@@ -151,7 +151,8 @@ class LivePG extends EventEmitter {
         triggers,
         data          : [],
         handlers      : [ handle ],
-        notifications : []
+        notifications : [],
+        initialized   : false
       }
 
       let pgHandle = await common.getClient(this.connStr)
@@ -210,6 +211,16 @@ class LivePG extends EventEmitter {
           filterHashProperties(update.diff), filterHashProperties(update.data))
       }
     }
+    else if(queryBuffer.initialized === false) {
+      // Initial update with empty data
+      for(let updateHandler of queryBuffer.handlers) {
+        updateHandler.emit('update',
+          { removed: null, moved: null, copied: null, added: [] },
+          [])
+      }
+    }
+
+    queryBuffer.initialized = true
   }
 
   _processNotification(payload) {

test/fixtures/variousQueries.es6

@@ -508,6 +508,30 @@ exports.cases.allExpression = {
   ]
 }
 
+// If initial result set is empty, an update event with an empty added array
+//  is emitted.
+exports.cases.initialEmpty = {
+  query: `SELECT score  FROM scores WHERE score > 100 ORDER BY score DESC`,
+  events: [
+    { diff: {
+      removed: null,
+      moved: null,
+      copied: null,
+      added: []
+    } },
+    { data: [] },
+    { perform: [
+      `UPDATE scores SET score = 200 WHERE id = 3`
+    ] },
+    { diff: {
+      removed: null,
+      moved: null,
+      copied: null,
+      added: [ { score: 200, _index: 1 } ]
+    } }
+  ]
+}
+
 exports.cases.sortMoved = {
   query: `SELECT score, assignment_id AS assign FROM scores ORDER BY score DESC`,
   events: [