Property '' does not exist on type 'Object'. Observable subscribe

Question

I have just started with Angular2 and I\'ve got an issue I cannot really understand.

I have some mock data created as such:

export const WORKFLOW_DAT         


        

Answer 1

When you tell typescript:

WORKFLOW_DATA: Object

You are telling it that WORKFLOW_DATA is a plain object with no attributes. When you later try to access WORKFLOW_DATA.testDataArray the compiler thinks you misusing the type.

If you want type checking on WORKFLOW_DATA you need to create an interface that describes your object.

Answer 2

The return type if your method is Observable<Object>. So when you subscribe, that will be the type passed. And there is no testDataArray on the Object type. You can do a couple things:

1. Type the data and return type differently

   WORKFLOW_DATA: { testDataArray: any } = []
   
   getWorkflowForEditor(): Observable<{ testDataArray: any }>
   

2. Or just type assert the response data to any

   console.log( (<any>WORKFLOW_DATA).testDataArray );
   

Answer 3

Typescript expects WORKFLOW_DATA to be Object here:

.subscribe( WORKFLOW_DATA => {} )

because you told it so:

  getWorkflowForEditor(): Observable<Object>

But Object doesn't have testDataArray property... You should either tell TypeScript that data can have any properties:

  getWorkflowForEditor(): Observable<any>

or use

console.log( WORKFLOW_DATA["testDataArray"] );