make execute input optional

Author: Ben-Wormald

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "sfn-sim",
-  "version": "1.3.0",
+  "version": "1.3.1",
   "description": "AWS Step Functions simulator for unit testing state machines",
   "keywords": [
     "aws",

package.json

@@ -1,5 +1,5 @@
 export interface StateMachine {
-  execute: (input: object) => Promise<object>;
+  execute: (input?: object) => Promise<object>;
 }
 
 export interface Options {

src/index.d.ts

@@ -24,7 +24,7 @@ const load = (definition, resources = [], overrideOptions = {}) => {
   }
 
   return {
-    execute: (input) => {
+    execute: (input = {}) => {
       const queryLanguage = definition.QueryLanguage || 'JSONPath';
 
       const Token = getTaskToken();