'Observable' is not a class derived from 'Observable'

Question

When trying to extend a class from a class in a node_modules the typescript compiler throws a error saying:

Property \'source\' is protected but

Answer 1

You can add a path mapping in your tsconfig.json to map the rxjs in your dependency to the one in your node_modules folder:

{
  "compilerOptions": {
    "baseUrl": ".",
    "paths": {
      "rxjs": ["node_modules/rxjs"]
    }
}

more documentation is available at the Typescript site