💄 reduce LOC for nested creation

lib/instance.js

@@ -671,30 +671,26 @@ module.exports = (function() {
             return Promise.map(self.options.include.filter(function (include) {
               return !(include.association instanceof BelongsTo);
             }), function (include) {
-              var instances = self.get(include.as)
-                , instance = instances;
+              var instances = self.get(include.as);
 
               if (!instances) return Promise.resolve();
-              if (Array.isArray(instances) && !instances.length) return Promise.resolve();
-
-              if (Array.isArray(instances)) {
-                return Promise.map(instances, function (instance) {
-                  if (include.association instanceof BelongsToMany) {
-                    return instance.save({transaction: options.transaction}).then(function () {
-                      var values = {};
-                      values[include.association.foreignKey] = self.get(self.Model.primaryKeyAttribute, {raw: true});
-                      values[include.association.otherKey] = instance.get(instance.Model.primaryKeyAttribute, {raw: true});
-                      return include.association.throughModel.create(values);
-                    });
-                  } else {
-                    instance.set(include.association.identifier, self.get(self.Model.primaryKeyAttribute, {raw: true}));
-                    return instance.save({transaction: options.transaction});    
-                  }
-                });
-              } else {
-                instance.set(include.association.identifier, self.get(self.Model.primaryKeyAttribute, {raw: true}));
-                return instance.save({transaction: options.transaction});
-              }
+              if (!Array.isArray(instances)) instances = [instances];
+              if (!instances.length) return Promise.resolve();
+
+              // Instances will be updated in place so we can safely treat HasOne like a HasMany
+              return Promise.map(instances, function (instance) {
+                if (include.association instanceof BelongsToMany) {
+                  return instance.save({transaction: options.transaction}).then(function () {
+                    var values = {};
+                    values[include.association.foreignKey] = self.get(self.Model.primaryKeyAttribute, {raw: true});
+                    values[include.association.otherKey] = instance.get(instance.Model.primaryKeyAttribute, {raw: true});
+                    return include.association.throughModel.create(values);
+                  });
+                } else {
+                  instance.set(include.association.identifier, self.get(self.Model.primaryKeyAttribute, {raw: true}));
+                  return instance.save({transaction: options.transaction});    
+                }
+              });
             });
           });
       });