feat(objects): add 2 new methods for object return by toEnum function

The toEnum function now return enum with method toString, includes that check if the given value can
be one of the enum, and a types method that return the enum keys.

Author: Itee

sources/cores/objects.js

@@ -219,20 +219,38 @@ export function createInterval ( particles, path, interval ) {
 
 export function toEnum ( enumValues ) {
 
-    return Object.freeze( Object.defineProperty( enumValues, 'toString', {
-        configurable: false,
-        enumerable:   false,
-        writable:     false,
-        value:        function _toString () {
-
-            const keys = Object.keys( this )
-            let result = ''
-            for ( let index = 0, numberOfValues = keys.length ; index < numberOfValues ; index++ ) {
-                result += `${keys[ index ]}, `
-            }
-            result = result.slice( 0, -2 )
-            return result
+    return Object.freeze( Object.defineProperties( enumValues, {
+        toString: {
+            configurable: false,
+            enumerable:   false,
+            writable:     false,
+            value:        function _toString () {
+
+                const keys = Object.keys( this )
+                let result = ''
+                for ( let index = 0, numberOfValues = keys.length ; index < numberOfValues ; index++ ) {
+                    result += `${keys[ index ]}, `
+                }
+                result = result.slice( 0, -2 )
+                return result
 
+            }
+        },
+        includes: {
+            configurable: false,
+            enumerable:   false,
+            writable:     false,
+            value: function _includes ( key ) {
+                return Object.values( this ).includes( key )
+            }
+        },
+        types:    {
+            configurable: false,
+            enumerable:   false,
+            writable:     false,
+            value: function _types () {
+                return Object.keys( this )
+            }
         }
     } ) )