Enable custom methods on singular relations

lib/relation-definition.js

@@ -90,6 +90,14 @@ function extendScopeMethods(definition, scopeMethods, ext) {
   return [].concat(customMethods || []);
 };
 
+function bindRelationMethods(relation, relationMethod, definition) {
+  var methods = definition.methods || {};
+  Object.keys(methods).forEach(function(m) {
+    if (typeof methods[m] !== 'function') return;
+    relationMethod[m] = methods[m].bind(relation);
+  });
+};
+
 /**
  * Relation definition class.  Use to define relationships between models.
  * @param {Object} definition
@@ -120,6 +128,7 @@ function RelationDefinition(definition) {
   this.options = definition.options || {};
   this.scope = definition.scope;
   this.embed = definition.embed === true;
+  this.methods = definition.methods || {};
 }
 
 RelationDefinition.prototype.toJSON = function () {
@@ -159,13 +168,22 @@ RelationDefinition.prototype.defineMethod = function(name, fn) {
   var relationName = this.name;
   var modelFrom = this.modelFrom;
   var definition = this;
+  var method;
+  if (definition.multiple) {
     var scope = this.modelFrom.scopes[this.name];
     if (!scope) throw new Error('Unknown relation scope: ' + this.name);
-  var method = scope.defineMethod(name, function() {
+    method = scope.defineMethod(name, function() {
       var relation = new relationClass(definition, this);
       return fn.apply(relation, arguments);
     });
-  if (fn.shared) {
+  } else {
+    definition.methods[name] = fn;
+    method = function() {
+      var rel = this[relationName];
+      return rel[name].apply(rel, arguments);
+    }
+  }
+  if (method && fn.shared) {
     sharedMethod(definition, name, method, fn);
     modelFrom.prototype['__' + name + '__' + relationName] = method;
   }
@@ -1152,7 +1170,8 @@ RelationDefinition.belongsTo = function (modelFrom, modelTo, params) {
     properties: params.properties,
     scope: params.scope,
     options: params.options,
-    polymorphic: polymorphic
+    polymorphic: polymorphic,
+    methods: params.methods
   });
 
   // Define a property for the scope so that we have 'this' for the scoped methods
@@ -1169,6 +1188,7 @@ RelationDefinition.belongsTo = function (modelFrom, modelTo, params) {
         relationMethod.build = relation.build.bind(relation);
         relationMethod._targetClass = definition.modelTo.modelName;
       }
+      bindRelationMethods(relation, relationMethod, definition);
       return relationMethod;
     }
   });
@@ -1466,7 +1486,8 @@ RelationDefinition.hasOne = function (modelFrom, modelTo, params) {
     properties: params.properties,
     scope: params.scope,
     options: params.options,
-    polymorphic: polymorphic
+    polymorphic: polymorphic,
+    methods: params.methods
   });
 
   modelTo.dataSource.defineForeignKey(modelTo.modelName, fk, modelFrom.modelName);
@@ -1483,6 +1504,7 @@ RelationDefinition.hasOne = function (modelFrom, modelTo, params) {
       relationMethod.update = relation.update.bind(relation);
       relationMethod.destroy = relation.destroy.bind(relation);
       relationMethod._targetClass = definition.modelTo.modelName;
+      bindRelationMethods(relation, relationMethod, definition);
       return relationMethod;
     }
   });
@@ -1740,7 +1762,8 @@ RelationDefinition.embedsOne = function (modelFrom, modelTo, params) {
     properties: params.properties,
     scope: params.scope,
     options: params.options,
-    embed: true
+    embed: true,
+    methods: params.methods
   });
 
   var opts = { type: modelTo };
@@ -1785,6 +1808,7 @@ RelationDefinition.embedsOne = function (modelFrom, modelTo, params) {
       relationMethod.destroy = relation.destroy.bind(relation);
       relationMethod.value = relation.embeddedValue.bind(relation);
       relationMethod._targetClass = definition.modelTo.modelName;
+      bindRelationMethods(relation, relationMethod, definition);
       return relationMethod;
     }
   });

test/relations.test.js

@@ -1617,12 +1617,30 @@ describe('relations', function () {
       (new Item).list.should.be.an.instanceOf(Function);
 
       // syntax 2 (new)
-      Fear.belongsTo('mind');
+      Fear.belongsTo('mind', {
+        methods: { check: function() { return true; } }
+      });
+      
       Object.keys((new Fear).toObject()).should.containEql('mindId');
       (new Fear).mind.should.be.an.instanceOf(Function);
       // (new Fear).mind.build().should.be.an.instanceOf(Mind);
     });
 
+    it('should setup a custom method on accessor', function() {
+      var rel = Fear.relations['mind'];
+      rel.defineMethod('other', function() {
+        return true;
+      })
+    });
+
+    it('should have setup a custom method on accessor', function() {
+      var f = new Fear();
+      f.mind.check.should.be.a.function;
+      f.mind.check().should.be.true;
+      f.mind.other.should.be.a.function;
+      f.mind.other().should.be.true;
+    });
+
     it('can be used to query data', function (done) {
       List.hasMany('todos', {model: Item});
       db.automigrate(function () {
@@ -1823,11 +1841,29 @@ describe('relations', function () {
     });
 
     it('can be declared using hasOne method', function () {
-      Supplier.hasOne(Account, { properties: { name: 'supplierName' } });
+      Supplier.hasOne(Account, { 
+        properties: { name: 'supplierName' },
+        methods: { check: function() { return true; } }
+      });
       Object.keys((new Account()).toObject()).should.containEql('supplierId');
       (new Supplier()).account.should.be.an.instanceOf(Function);
     });
 
+    it('should setup a custom method on accessor', function() {
+      var rel = Supplier.relations['account'];
+      rel.defineMethod('other', function() {
+        return true;
+      })
+    });
+
+    it('should have setup a custom method on accessor', function() {
+      var s = new Supplier();
+      s.account.check.should.be.a.function;
+      s.account.check().should.be.true;
+      s.account.other.should.be.a.function;
+      s.account.other().should.be.true;
+    });
+
     it('can be used to query data', function (done) {
       db.automigrate(function () {
         Supplier.create({name: 'Supplier 1'}, function (e, supplier) {
@@ -2213,7 +2249,8 @@ describe('relations', function () {
 
     it('can be declared using embedsOne method', function (done) {
       Person.embedsOne(Passport, {
-        default: {name: 'Anonymous'} // a bit contrived
+        default: {name: 'Anonymous'}, // a bit contrived
+        methods: { check: function() { return true; } }
       });
       Person.embedsOne(Address); // all by default
       db.automigrate(done);
@@ -2228,6 +2265,21 @@ describe('relations', function () {
       p.passportItem.destroy.should.be.a.function;
     });
 
+    it('should setup a custom method on accessor', function() {
+      var rel = Person.relations['passportItem'];
+      rel.defineMethod('other', function() {
+        return true;
+      })
+    });
+
+    it('should have setup a custom method on accessor', function() {
+      var p = new Person();
+      p.passportItem.check.should.be.a.function;
+      p.passportItem.check().should.be.true;
+      p.passportItem.other.should.be.a.function;
+      p.passportItem.other().should.be.true;
+    });
+
     it('should behave properly without default or being set', function (done) {
       var p = new Person();
       should.not.exist(p.address);