Fixed undefined and null responseParameter values

[jormaechea]

Handled undefined and null reponseParameter values.

Closes #758

[dnalborczyk]

thank you @jormaechea !

[jormaechea]

@dnalborczyk any idea of when this Fix will be released? 😄

[dnalborczyk]

any idea of when this Fix will be released?

hey @jormaechea should be very soon!

I'm in the midst of adding more tests. Do you have a simple scenario in form of a serverless.yml and a handler file (which fails without your fix) I could add to the tests? That would be great.

[jormaechea]

@dnalborczyk the test case for this one is very similar to the other PR. This time, trying to access an undefined property.

serverless.yml

service: TestService

provider:
  name: aws
  runtime: nodejs10.x
  region: us-east-1

functions:
  HelloWorldApi:
    handler: index.handler
    description: Hello World API
    events:
      - http:
          integration: lambda
          path: hello-world
          method: get
          responses:
            default:
              responseModels:
                application/json;charset=UTF-8: Empty
              responseParameters:
                method.response.header.x-foo: "integration.response.body.more-foo.property-of-undefined"
              responseTemplates:
                application/json;charset=UTF-8: ""
              statusCode: 200

plugins:
  - serverless-offline

index.js

module.exports.handler = async () => {
	return {
		foo: 'bar'
	};
};

[dnalborczyk]

thank you @jormaechea !

[dnalborczyk]

any idea of when this Fix will be released?

@jormaechea

released as part of v6.0.0-alpha.0: https://github.com/dherault/serverless-offline/releases/tag/v6.0.0-alpha.0