diff --git a/lib/model.js b/lib/model.js
index d9d65a09..6d6bc19b 100644
--- a/lib/model.js
+++ b/lib/model.js
@@ -418,6 +418,12 @@ ModelBaseClass.toString = function() {
  * @returns {Object} returns Plain JSON object
  */
 ModelBaseClass.prototype.toObject = function(onlySchema, removeHidden, removeProtected) {
+  if (typeof onlySchema === 'object' && onlySchema != null) {
+    var options = onlySchema;
+    onlySchema = options.onlySchema;
+    removeHidden = options.removeHidden;
+    removeProtected = options.removeProtected;
+  }
   if (onlySchema === undefined) {
     onlySchema = true;
   }
diff --git a/test/loopback-dl.test.js b/test/loopback-dl.test.js
index a59480d3..17757b47 100644
--- a/test/loopback-dl.test.js
+++ b/test/loopback-dl.test.js
@@ -133,8 +133,8 @@ describe('ModelBuilder', function() {
 
     // Predefined property bio should be kept
     user.toObject().should.have.property('bio', 'me');
-    user.toObject(true).should.have.property('bio', 'me');
-    user.toObject(false).should.have.property('bio', 'me');
+    user.toObject({onlySchema: true}).should.have.property('bio', 'me');
+    user.toObject({onlySchema: false}).should.have.property('bio', 'me');
 
     done(null, User);
   });
diff --git a/types/datasource.d.ts b/types/datasource.d.ts
index 382f4cbf..35ac5a20 100644
--- a/types/datasource.d.ts
+++ b/types/datasource.d.ts
@@ -83,7 +83,9 @@ export declare class DataSource {
 
   DataAccessObject: AnyObject & {prototype: AnyObject};
 
-  constructor(name?: string, settings?: Options, modelBuilder?: ModelBuilder);
+  constructor(name: string, settings?: Options, modelBuilder?: ModelBuilder);
+
+  constructor(settings?: Options, modelBuilder?: ModelBuilder);
 
   constructor(
     connectorModule: Connector,
diff --git a/types/model.d.ts b/types/model.d.ts
index 97743b69..dc12c48b 100644
--- a/types/model.d.ts
+++ b/types/model.d.ts
@@ -92,7 +92,7 @@ export declare class ModelDefinition extends EventEmitter implements Schema {
 }
 
 /**
- * Base model class
+ * Base class for LoopBack 3.x models
  */
 export declare class ModelBase {
   static dataSource?: DataSource;
@@ -135,15 +135,16 @@ export declare class ModelBase {
   static getUpdateOnlyProperties(): string[];
 
   /**
-   * Model class: base class for all persistent objects.
+   * Constructor for ModelBase
    *
-   * `ModelBaseClass` mixes `Validatable` and `Hookable` classes methods
+   * NOTE: We have to use `constructor(...args: any[]);` so that it can be used
+   * for `return class extends superClass`.
    *
-   * @class
    * @param {AnyObject} data Initial object data
    * @param {Options} options An object to control the instantiation
    */
-  constructor(data: AnyObject, options?: Options);
+  constructor(...args: any[]);
+  // constructor(data: AnyObject, options?: Options);
 
   /**
    * Convert the model instance to a plain json object
@@ -160,20 +161,17 @@ export declare class ModelBase {
    * Convert model instance to a plain JSON object.
    * Returns a canonical object representation (no getters and setters).
    *
-   * @param {boolean} onlySchema Restrict properties to dataSource only.
+   * @param options Options for the conversion
+   * @property {boolean} onlySchema Restrict properties to dataSource only.
    * Default is false.  If true, the function returns only properties defined
    * in the schema;  Otherwise it returns all enumerable properties.
-   * @param {boolean} removeHidden Boolean flag as part of the transformation.
+   * @property {boolean} removeHidden Boolean flag as part of the transformation.
    * If true, then hidden properties should not be brought out.
-   * @param {boolean} removeProtected Boolean flag as part of the transformation.
+   * @property {boolean} removeProtected Boolean flag as part of the transformation.
    * If true, then protected properties should not be brought out.
    * @returns {object} returns Plain JSON object
    */
-  toObject(
-    onlySchema?: boolean,
-    removeHidden?: boolean,
-    removeProtected?: boolean,
-  ): AnyObject;
+  toObject(options?: Options): AnyObject;
 
   /**
    * Define a property on the model.