Add support for hasMany-through and more tests

lib/datasource.js

@@ -12,6 +12,7 @@ var EventEmitter = require('events').EventEmitter;
 var util = require('util');
 var path = require('path');
 var fs = require('fs');
+var assert = require('assert');
 var async = require('async');
 
 var existsSync = fs.existsSync || path.existsSync;
@@ -302,6 +303,13 @@ DataSource.prototype.setup = function(name, settings) {
     };
 };
 
+function isModelClass(cls) {
+    if(!cls) {
+        return false;
+    }
+    return cls.prototype instanceof ModelBaseClass;
+}
+
 /**
  * Define a model class
  *
@@ -383,33 +391,62 @@ DataSource.prototype.createModel = DataSource.prototype.define = function define
     var relations = settings.relationships || settings.relations;
 
     // Create a function for the closure in the loop
-    var createListener = function(name, relation, targetModel) {
+    var createListener = function (name, relation, targetModel, throughModel) {
-        targetModel.once('defined', function(model) {
+        if (targetModel && targetModel.settings.unresolved) {
+            targetModel.once('defined', function (model) {
+                // Check if the through model doesn't exist or resolved
+                if (!throughModel || !throughModel.settings.unresolved) {
                     // The target model is resolved
                     var params = {
                         foreignKey: relation.foreignKey,
                         as: name,
                         model: model
                     };
+                    if (throughModel) {
+                        params.through = throughModel;
+                    }
                     NewClass[relation.type].call(NewClass, name, params);
+                }
             });
+        }
+        if (throughModel && throughModel.settings.unresolved) {
+            // Set up a listener to the through model
+            throughModel.once('defined', function (model) {
+                if (!targetModel.settings.unresolved) {
+                    // The target model is resolved
+                    var params = {
+                        foreignKey: relation.foreignKey,
+                        as: name,
+                        model: targetModel,
+                        through: model
+                    };
+                    NewClass[relation.type].call(NewClass, name, params);
+                }
+            });
+        }
     };
 
     // Set up the relations
     if (relations) {
         for (var rn in relations) {
             var r = relations[rn];
-            if (!r.type) {
+            assert(['belongsTo', 'hasMany', 'hasAndBelongsToMany'].indexOf(r.type) !== -1, "Invalid relation type: " + r.type);
-                throw new Error('Relation type is required for ' + r);
+            var targetModel = isModelClass(r.model) ? r.model : this.models[r.model];
-            }
-            var targetModel = this.models[r.model];
             if(!targetModel) {
                 // The target model doesn't exist, let create a place holder for it
                 targetModel = this.define(r.model, {}, {unresolved: true});
             }
-            if(targetModel.settings.unresolved) {
+            var throughModel = null;
+            if(r.through) {
+                throughModel = isModelClass(r.through) ? r.through : this.models[r.through];
+                if(!throughModel) {
+                    // The through model doesn't exist, let create a place holder for it
+                    throughModel = this.define(r.through, {}, {unresolved: true});
+                }
+            }
+            if(targetModel.settings.unresolved || (throughModel && throughModel.settings.unresolved)) {
                 // Create a listener to defer the relation set up
-                createListener(rn, r, targetModel);
+                createListener(rn, r, targetModel, throughModel);
             } else {
                     // The target model is resolved
                     var params = {
@@ -417,6 +454,9 @@ DataSource.prototype.createModel = DataSource.prototype.define = function define
                         as: rn,
                         model: targetModel
                     };
+                    if(throughModel) {
+                        params.through = throughModel;
+                    }
                     NewClass[r.type].call(NewClass, rn, params);
                 }
         }

test/loopback-dl.test.js

@@ -444,6 +444,10 @@ describe('Load models with relations', function () {
         var ds = new DataSource('memory');
 
         var User = ds.define('User', {name: String}, {relations: {posts: {type: 'hasMany', model: 'Post'}, accounts: {type: 'hasMany', model: 'Account'}}});
+
+        assert(!User.relations['posts']);
+        assert(!User.relations['accounts']);
+
         var Post = ds.define('Post', {userId: Number, content: String}, {relations: {user: {type: 'belongsTo', model: 'User'}}});
 
         var Account = ds.define('Account', {userId: Number, type: String}, {relations: {user: {type: 'belongsTo', model: 'User'}}});
@@ -489,6 +493,44 @@ describe('Load models with relations', function () {
 
     });
 
+    it('should throw if the relation type is invalid', function (done) {
+        var ds = new DataSource('memory');
+
+        var Post = ds.define('Post', {userId: Number, content: String});
+
+        try {
+            var User = ds.define('User', {name: String}, {relations: {posts: {type: 'hasXYZ', model: 'Post'}}});
+        } catch (e) {
+            done();
+        }
+
+    });
+
+    it('should handle hasMany through', function (done) {
+        var ds = new DataSource('memory');
+        var Physician = ds.createModel('Physician', {
+            name: String
+        }, {relations: {patients: {model: 'Patient', type: 'hasMany', through: 'Appointment'}}});
+
+        var Patient = ds.createModel('Patient', {
+            name: String
+        }, {relations: {physicians: {model: 'Physician', type: 'hasMany', through: 'Appointment'}}});
+
+        assert(!Physician.relations['patients']); // Appointment hasn't been resolved yet
+        assert(!Patient.relations['physicians']); // Appointment hasn't been resolved yet
+
+        var Appointment = ds.createModel('Appointment', {
+            physicianId: Number,
+            patientId: Number,
+            appointmentDate: Date
+        }, {relations: {patient: {type: 'belongsTo', model: 'Patient'}, physician: {type: 'belongsTo', model: 'Physician'}}});
+
+        assert(Physician.relations['patients']);
+        assert(Patient.relations['physicians']);
+        done();
+    });
+
+
 });
 
 describe('Load models from json', function () {