Indexer.

benpickles · benpickles · commit f42bb6e092b2 · 2012-03-12T14:33:56.000Z
diff --git a/src/indexer.js b/src/indexer.js
@@ -0,0 +1,29 @@
+;(function(Model) {
+  Model.Indexer = function(collection, attribute) {
+    this.collection = collection
+    this.attribute = attribute
+    this.index = {}
+    this.collection.on("add", this.add, this)
+    this.collection.on("remove", this.remove, this)
+    this.collection.forEach(this.add, this)
+  }
+
+  Model.Indexer.prototype.add = function(model) {
+    this.get(model.get(this.attribute)).add(model)
+    model.on("change:" + this.attribute, this.change, this)
+  }
+
+  Model.Indexer.prototype.change = function(model, from, to) {
+    this.get(from).remove(model)
+    this.get(to).add(model)
+  }
+
+  Model.Indexer.prototype.get = function(key) {
+    return this.index[key] || (this.index[key] = new Model.Collection())
+  }
+
+  Model.Indexer.prototype.remove = function(model) {
+    this.get(model.get(this.attribute)).remove(model)
+    model.off("change:" + this.attribute, this.change, this)
+  }
+})(Model);
diff --git a/src/model_model.js b/src/model_model.js
@@ -18,6 +18,8 @@
   }
 
   function set(name, value) {
+    var from = this.get(name)
+
     // Don't write to attributes yet, store in changes for now.
     if (this.attributes[name] === value) {
       // Clean up any stale changes.
@@ -26,7 +28,7 @@
       this.changes[name] = value
     }
 
-    this.emit("change:" + name, this)
+    this.emit("change:" + name, this, from, value)
   }
 
   Model.Model.prototype = {
diff --git a/test/index.html b/test/index.html
@@ -25,6 +25,7 @@
 <script src="../src/model_rest.js"></script>
 <script src="../src/model_uid.js"></script>
 <script src="../src/model_version.js"></script>
+<script src="../src/indexer.js"></script>
 
 <!-- Helpers -->
 <script src="javascripts/helpers.js"></script>
@@ -41,6 +42,7 @@
 <script src="tests/model_local_storage_test.js"></script>
 <script src="tests/inheritance_test.js"></script>
 <script src="tests/plugin_test.js"></script>
+<script src="tests/indexer_test.js"></script>
 </head>
 <body>
 <h1 id="qunit-header">js-model Tests</h1>
diff --git a/test/tests/indexer_test.js b/test/tests/indexer_test.js
@@ -0,0 +1,39 @@
+module("Model.Indexer")
+
+test("manages its index correctly", function() {
+  var Story = Model("story")
+
+  var story1 = new Story({ project_id: 1 })
+  var story2 = new Story({ project_id: 2 })
+  var story3 = new Story({ project_id: 3 })
+
+  Story.collection.push(story1, story2, story3)
+
+  var index = new Model.Indexer(Story.collection, "project_id")
+
+  ok(index.get(1).first() === story1, "index is populated")
+  ok(index.get(2).first() === story2, "index is populated")
+  ok(index.get(3).first() === story3, "index is populated")
+
+  var story4 = new Story({ project_id: 4 })
+
+  equal(index.get(4).length, 0, "empty keys respond to the same interface")
+
+  Story.collection.add(story4)
+
+  equal(index.get(4).length, 1, "index includes models added to the collection")
+
+  story4.set("project_id", 1)
+
+  equal(index.get(1).length, 2, "index is kept up to date with updated models")
+  ok(index.get(1).first() === story1)
+  ok(index.get(1).last() === story4)
+  equal(index.get(4).length, 0)
+
+  equal(story2._events["change:project_id"].length, 1, "just checking")
+
+  Story.collection.remove(story2)
+
+  equal(index.get(2).length, 0, "model is removed from the index")
+  equal(story2._events["change:project_id"].length, 0, "Indexer callbacks are cleaned up")
+})

Original file line number	Diff line number	Diff line change
`@@ -18,6 +18,8 @@`
`18`	`18`	`}`
`19`	`19`
`20`	`20`	`function set(name, value) {`
	`21`	`+ var from = this.get(name)`
	`22`	`+`
`21`	`23`	`// Don't write to attributes yet, store in changes for now.`
`22`	`24`	`if (this.attributes[name] === value) {`
`23`	`25`	`// Clean up any stale changes.`
`@@ -26,7 +28,7 @@`
`26`	`28`	`this.changes[name] = value`
`27`	`29`	`}`
`28`	`30`
`29`		`- this.emit("change:" + name, this)`
	`31`	`+ this.emit("change:" + name, this, from, value)`
`30`	`32`	`}`
`31`	`33`
`32`	`34`	`Model.Model.prototype = {`