change readme

add some check

Author: vkkis93

README.md

@@ -52,7 +52,7 @@ You must have this plugin installed and correctly specified statemachine definit
 Example of statemachine definition you can see [here](https://github.com/horike37/serverless-step-functions#setup).
 
 # Usage
-After all steps are done, need to add to section **custom** in serverless.yml the key **stepFunctionsOffline** with properties *stateName*: path to lambda function.
+After all steps are done, need to add to section **custom** in serverless.yml the key **stepFunctionsOffline** with properties *stateName*: name of lambda function.
 
 For example:
 
@@ -66,10 +66,10 @@ plugins:
 
 custom:
   stepFunctionsOffline:
-    StepOne: firstLambda
+    stepOne: firstLambda (v2.0)
     # ...
     # ...
-    stepTwo: secondLambda
+    stepTwo: secondLambda (v2.0)
 
 functions:
     firstLambda:
@@ -132,9 +132,6 @@ By default `process.env.STEP_IS_OFFLINE = true`.
  - [ ] Add unit tests - to make plugin stable (next step) - [ ] Support fields *Retry*, *Catch*
  - [ ] Support other languages except node.js
 
-
-If you have any questions, feel free to contact me: vkkis1993@gmail.com
-
 # License
 
 MIT

build.js

@@ -88,6 +88,10 @@ module.exports = {
             process.env = Object.assign({}, this.environmentVariables);
             let f = this.variables[currentStateName];
             f = this.functions[f];
+            if (!f) {
+                this.cliLog(`Function "${currentStateName}" does not presented in serverless.yml`);
+                process.exit(1);
+            }
             const {handler, filePath} = this._findFunctionPathAndHandler(f.handler);
             // if function has additional variables - attach it to function
             if (f.environment) {