alternate syntax for computed field definition using object literal

mxriverlynn · Sep 24, 2012 · 660508d · 660508d
1 parent 021866a
commit 660508d
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Showing 3 changed files with 53 additions and 33 deletions.
diff --git a/readme.md b/readme.md
@@ -33,10 +33,13 @@ var Model = Backbone.Model.extend({
   // tell it what field to `set` on the model
   // tell it what fields this one depends on
   // give it a callback function to compute the value when any dependent field changes
-  computedField: Backbone.Compute("computedField", ["f1", "f2"], function(fields){
-    fieldList = fields;
-    return fields.f1 + "-" + fields.f2
-  })
+  someField: {
+    fields: ["f1", "f2"], 
+    compute: function(fields){
+      fieldList = fields;
+      return fields.f1 + "-" + fields.f2
+    }
+  }
 
 });
 
@@ -46,14 +49,14 @@ var model = new Model({
 });
 
 // get the current value
-model.get("computedField"); // => "foo-bar"
+model.get("someField"); // => "foo-bar"
 
 // re-run the computation, `set` the current value and return it
-model.computedField(); // => "foo-bar"
+model.someField(); // => "foo-bar"
 
 
 // Handle "change" events for the computed field
-model.on("change:computedField", function(){
+model.on("change:someField", function(){
   // do stuff when the computed field changes
 });
 
@@ -64,8 +67,8 @@ model.set({
 });
 
 // get the updated value
-model.get("computedField"); // => "boo-far"
-model.computedField(); // => "boo-far"
+model.get("someField"); // => "boo-far"
+model.someField(); // => "boo-far"
 ```
 
 ## License

diff --git a/spec/javascripts/computedField.spec.js b/spec/javascripts/computedField.spec.js
@@ -8,10 +8,13 @@ describe("computed fields", function(){
         Backbone.Compute(this);
       },
 
-      computedField: Backbone.Compute("computedField", "anotherField", function(fields){
-        fieldList = fields;
-        return fields.anotherField + "-bar"
-      })
+      computedField: {
+        fields: "anotherField", 
+        compute: function(fields){
+          fieldList = fields;
+          return fields.anotherField + "-bar"
+        }
+      }
     });
 
     beforeEach(function(){
@@ -37,10 +40,13 @@ describe("computed fields", function(){
         Backbone.Compute(this);
       },
 
-      computedField: Backbone.Compute("computedField", ["f1", "f2"], function(fields){
-        fieldList = fields;
-        return fields.f1 + "-" + fields.f2
-      })
+      computedField: {
+        fields: ["f1", "f2"], 
+        compute: function(fields){
+          fieldList = fields;
+          return fields.f1 + "-" + fields.f2
+        }
+      }
     });
 
     beforeEach(function(){
@@ -68,10 +74,13 @@ describe("computed fields", function(){
         Backbone.Compute(this);
       },
 
-      computedField: Backbone.Compute("computedField", ["f1", "f2"], function(fields){
-        fieldList = fields;
-        return fields.f1 + "-" + fields.f2
-      })
+      computedField: {
+        fields: ["f1", "f2"], 
+        compute: function(fields){
+          fieldList = fields;
+          return fields.f1 + "-" + fields.f2
+        }
+      }
     });
 
     beforeEach(function(){
@@ -96,10 +105,13 @@ describe("computed fields", function(){
         Backbone.Compute(this);
       },
 
-      computedField: Backbone.Compute("computedField", ["f1", "f2"], function(fields){
-        fieldList = fields;
-        return fields.f1 + "-" + fields.f2
-      })
+      computedField: {
+        fields: ["f1", "f2"], 
+        compute: function(fields){
+          fieldList = fields;
+          return fields.f1 + "-" + fields.f2
+        }
+      }
     });
 
     beforeEach(function(){
@@ -137,7 +149,10 @@ describe("computed fields", function(){
           Backbone.Compute(this);
         },
 
-        computedField: Backbone.Compute("computedField", ["f1", "f2"], handler)
+        computedField: {
+          fields: ["f1", "f2"], 
+          compute: handler
+        }
       });
 
       model = new Model({

diff --git a/src/backbone.compute.js b/src/backbone.compute.js
@@ -8,7 +8,13 @@ Backbone.Compute = (function(Backbone, _){
   // model's `initialize` function.
   function initializeModel(obj){
     for(var field in obj){
-      if (obj[field] && obj[field].computedField){
+      var computeAttr = obj[field];
+      if (computeAttr
+          && computeAttr.fields
+          && computeAttr.compute
+         ){
+
+        obj[field] = computeField(field, computeAttr.fields, computeAttr.compute);
         obj[field].call(obj);
       }
     }
@@ -70,12 +76,8 @@ Backbone.Compute = (function(Backbone, _){
   // The raw API for computed fields. Determines whether
   // you are attempting to initialize the model or define
   // a computed field, and call the correct behavior.
-  var Compute = function(){
-    if (arguments.length === 1){
-      return initializeModel(arguments[0]);
-    } else {
-      return computeField.apply(null, arguments);
-    }
+  var Compute = function(model){
+    return initializeModel(model);
   };
 
   return Compute;