[apollo-datasource-rest] - Reuse classes outside of Apollo Server context

I’m using the package apollo-datasource-rest alongside Apollo Server to manage external REST requests and its working fine.

module.exports = class AuthenticationAPI extends RESTDataSource {
  constructor() {
    super()
    this.baseURL = REST_ENDPOINT
  }

  async login(args) {
    return this.post('/FormLogin/login', args)
  }

}

I would like to call those same class methods on server init before actually launching the Apollo Server. Naively I tried to instanciate the class with new and then call methods on the instance but at the moment I’m getting this error when class is instantiated outside the apollo server “context”.

// from anywhere, executed outside of apollo server context
const authenticationAPI = new AuthenticationAPI()
this.authenticationAPI.login(data)
-------
UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'fetch' of undefined
    at AuthenticationAPI.<anonymous> (/<folder>/node_modules/apollo-datasource-rest/dist/RESTDataSource.js:151:63)

Is there a way to archieve this or will I have to duplicate same fetching methods?

[Renaud009]

Actually relates to this https://github.com/apollographql/apollo-server/issues/2240

Calling initialize() function with empty object fixed my problem.

this.authenticationAPI = new AuthenticationAPI()
this.authenticationAPI.initialize({})
const token = await this.authenticationAPI.login(credentials)

[robe007]

I had the same problem with apollo-datasource-rest combined with graphql-yoga, but with the clue of @Renaud009, now it works.

You can see my comments about it here