diff --git a/lodash/lodash.d.ts b/lodash/lodash.d.ts
index d50edec131..bc629f6ece 100644
--- a/lodash/lodash.d.ts
+++ b/lodash/lodash.d.ts
@@ -287,12 +287,12 @@ declare module _ {
         * @param array Array to compact.
         * @return (Array) Returns a new array of filtered values.
         **/
-        compact<T>(array: Array<T>): T[];
+        compact<T>(array?: Array<T>): T[];
 
         /**
         * @see _.compact
         **/
-        compact<T>(array: List<T>): T[];
+        compact<T>(array?: List<T>): T[];
     }
 
     interface LoDashArrayWrapper<T> {
@@ -312,13 +312,13 @@ declare module _ {
         * @return Returns a new array of filtered values.
         **/
         difference<T>(
-            array: Array<T>,
+            array?: Array<T>,
             ...others: Array<T>[]): T[];
         /**
         * @see _.difference
         **/
         difference<T>(
-            array: List<T>,
+            array?: List<T>,
             ...others: List<T>[]): T[];
     }
 
@@ -456,12 +456,12 @@ declare module _ {
         * @param array Retrieves the first element of this array.
         * @return Returns the first element of `array`.
         **/
-        first<T>(array: Array<T>): T;
+        first<T>(array?: Array<T>): T;
 
         /**
         * @see _.first
         **/
-        first<T>(array: List<T>): T;
+        first<T>(array?: List<T>): T;
 
         /**
         * @see _.first
@@ -5701,7 +5701,7 @@ declare module _ {
         * @param value The value to check.
         * @return True if the value is an arguments object, else false.
         **/
-        isArguments(value: any): boolean;
+        isArguments(value?: any): boolean;
     }
 
     //_.isArray
@@ -5711,7 +5711,7 @@ declare module _ {
         * @param value The value to check.
         * @return True if the value is an array, else false.
         **/
-        isArray(value: any): boolean;
+        isArray(value?: any): boolean;
     }
 
     //_.isBoolean
@@ -5721,7 +5721,7 @@ declare module _ {
         * @param value The value to check.
         * @return True if the value is a boolean value, else false.
         **/
-        isBoolean(value: any): boolean;
+        isBoolean(value?: any): boolean;
     }
 
     //_.isDate
@@ -5731,7 +5731,7 @@ declare module _ {
         * @param value The value to check.
         * @return True if the value is a date, else false.
         **/
-        isDate(value: any): boolean;
+        isDate(value?: any): boolean;
     }
 
     //_.isElement
@@ -5741,7 +5741,7 @@ declare module _ {
         * @param value The value to check.
         * @return True if the value is a DOM element, else false.
         **/
-        isElement(value: any): boolean;
+        isElement(value?: any): boolean;
     }
 
     //_.isEmpty
@@ -5752,22 +5752,7 @@ declare module _ {
         * @param value The value to inspect.
         * @return True if the value is empty, else false.
         **/
-        isEmpty(value: any[]): boolean;
-
-        /**
-        * @see _.isEmpty
-        **/
-        isEmpty(value: Dictionary<any>): boolean;
-
-        /**
-        * @see _.isEmpty
-        **/
-        isEmpty(value: string): boolean;
-
-        /**
-        * @see _.isEmpty
-        **/
-        isEmpty(value: any): boolean;
+        isEmpty(value?: any[]|Dictionary<any>|string|any): boolean;
     }
     
     //_.isError
@@ -5796,8 +5781,8 @@ declare module _ {
         * @return True if the values are equivalent, else false.
         **/
         isEqual(
-            a: any,
-            b: any,
+            a?: any,
+            b?: any,
             callback?: (a: any, b: any) => boolean,
             thisArg?: any): boolean;
     }
@@ -5812,7 +5797,7 @@ declare module _ {
         * @param value The value to check.
         * @return True if the value is finite, else false.
         **/
-        isFinite(value: any): boolean;
+        isFinite(value?: any): boolean;
     }
 
     //_.isFunction
@@ -5822,7 +5807,7 @@ declare module _ {
         * @param value The value to check.
         * @return True if the value is a function, else false.
         **/
-        isFunction(value: any): boolean;
+        isFunction(value?: any): boolean;
     }
 
     //_.isNaN
@@ -5835,7 +5820,7 @@ declare module _ {
         * @param value The value to check.
         * @return True if the value is NaN, else false.
         **/
-        isNaN(value: any): boolean;
+        isNaN(value?: any): boolean;
     }
 
     //_.isNull
@@ -5845,7 +5830,7 @@ declare module _ {
         * @param value The value to check.
         * @return True if the value is null, else false.
         **/
-        isNull(value: any): boolean;
+        isNull(value?: any): boolean;
     }
 
     //_.isNumber
@@ -5857,7 +5842,7 @@ declare module _ {
         * @param value The value to check.
         * @return True if the value is a number, else false.
         **/
-        isNumber(value: any): boolean;
+        isNumber(value?: any): boolean;
     }
 
     //_.isObject
@@ -5868,7 +5853,7 @@ declare module _ {
         * @param value The value to check.
         * @return True if the value is an object, else false.
         **/
-        isObject(value: any): boolean;
+        isObject(value?: any): boolean;
     }
 
     //_.isPlainObject
@@ -5878,7 +5863,7 @@ declare module _ {
         * @param value The value to check.
         * @return True if value is a plain object, else false.
         **/
-        isPlainObject(value: any): boolean;
+        isPlainObject(value?: any): boolean;
     }
 
     //_.isRegExp
@@ -5888,7 +5873,7 @@ declare module _ {
         * @param value The value to check.
         * @return True if the value is a regular expression, else false.
         **/
-        isRegExp(value: any): boolean;
+        isRegExp(value?: any): boolean;
     }
 
     //_.isString
@@ -5898,7 +5883,7 @@ declare module _ {
         * @param value The value to check.
         * @return True if the value is a string, else false.
         **/
-        isString(value: any): boolean;
+        isString(value?: any): boolean;
     }
 
     //_.isUndefined
@@ -5908,7 +5893,7 @@ declare module _ {
         * @param value The value to check.
         * @return True if the value is undefined, else false.
         **/
-        isUndefined(value: any): boolean;
+        isUndefined(value?: any): boolean;
     }
 
     //_.keys
@@ -5918,7 +5903,7 @@ declare module _ {
         * @param object The object to inspect.
         * @return An array of property names.
         **/
-        keys(object: any): string[];
+        keys(object?: any): string[];
     }
 
     interface LoDashObjectWrapper<T> {
@@ -6068,7 +6053,7 @@ declare module _ {
         * @param object The object to inspect.
         * @return Aew array of key-value pairs.
         **/
-        pairs(object: any): any[][];
+        pairs(object?: any): any[][];
     }
 
     interface LoDashObjectWrapper<T> {
@@ -6180,7 +6165,7 @@ declare module _ {
         * @param object The object to inspect.
         * @return Returns an array of property values.
         **/
-        values(object: any): any[];
+        values(object?: any): any[];
     }
 
     /**********
@@ -6206,10 +6191,8 @@ declare module _ {
         trimLeft(str?: string, chars?: string): string;
         trimRight(str?: string, chars?: string): string;
         trunc(str?: string, len?: number): string;
-        trunc(str?: string, options?: { length?: number; omission?: string; separator?: string }): string;
-        trunc(str?: string, options?: { length?: number; omission?: string; separator?: RegExp }): string;
-        words(str?: string, pattern?: string): string[];
-        words(str?: string, pattern?: RegExp): string[];
+        trunc(str?: string, options?: { length?: number; omission?: string; separator?: string|RegExp }): string;
+        words(str?: string, pattern?: string|RegExp): string[];
     }
 
     //_.parseInt
@@ -6224,7 +6207,7 @@ declare module _ {
         * @param radix The radix used to interpret the value to parse.
         * @return The new integer value.
         **/
-        parseInt(value: string, radix?: number): number;
+        parseInt(value?: string, radix?: number): number;
     }
 
     /*************
@@ -6237,7 +6220,7 @@ declare module _ {
         * @param string The string to escape.
         * @return The escaped string.
         **/
-        escape(str: string): string;
+        escape(str?: string): string;
     }
 
     //_.identity
@@ -6247,7 +6230,7 @@ declare module _ {
         * @param value Any value.
         * @return value.
         **/
-        identity<T>(value: T): T;
+        identity<T>(value?: T): T;
     }
 
     //_.mixin
@@ -6256,7 +6239,7 @@ declare module _ {
         * Adds function properties of a source object to the lodash function and chainable wrapper.
         * @param object The object of function properties to add to lodash.
         **/
-        mixin(object: Dictionary<(value: any) => any>): void;
+        mixin(object?: Dictionary<(value: any) => any>): void;
     }
 
     //_.noConflict