added _.invert definition

lodash/lodash-tests.ts

@@ -583,6 +583,8 @@ _.functions(_);
 
 _.has({ 'a': 1, 'b': 2, 'c': 3 }, 'b');
 
+_.invert({ 'first': 'moe', 'second': 'larry' });
+
 var mergeNames = {
   'stooges': [
     { 'name': 'moe' },
@@ -629,7 +631,6 @@ _.merge(mergeFood, mergeOtherFood, function(a, b) {
 _.keys({ one: 1, two: 2, three: 3 });
 _.values({ one: 1, two: 2, three: 3 });
 _.pairs({ one: 1, two: 2, three: 3 });
-_.invert({ Moe: "Moses", Larry: "Louis", Curly: "Jerome" });
 _.pick({ name: 'moe', age: 50, userid: 'moe1' }, 'name', 'age');
 _.omit({ name: 'moe', age: 50, userid: 'moe1' }, 'name');
 _.omit({ name: 'moe', age: 50, userid: 'moe1' }, 'name', 'age');

lodash/lodash.d.ts

@@ -2339,6 +2339,13 @@ declare module _ {
 	**/
 	export function has(object: any, property: string): boolean;
 
+	/**
+	* Creates an object composed of the inverted keys and values of the given object.
+	* @param object The object to invert.
+	* @return The created inverted object.
+	**/
+	export function invert(object: any): any;
+
 	/**
 	* Recursively merges own enumerable properties of the source object(s), that don't resolve 
 	* to undefined into the destination object. Subsequent sources will overwrite property 
@@ -2515,14 +2522,6 @@ declare module _ {
 	**/
 	export function pairs(object: any): any[][];
 
-	/**
-	* Returns a copy of the object where the keys have become the values and the values the keys.
-	* For this to work, all of your object's values should be unique and string serializable.
-	* @param object Object to invert key/value pairs.
-	* @return An inverted key/value paired version of `object`.
-	**/
-	export function invert(object: any): any;
-
 	/**
 	* Return a copy of the object, filtered to only have values for the whitelisted keys
 	* (or array of valid keys).