auh_flow_step2.js

let result = await fetch({
  api: "http://localhost:3000/users/auth/google_oauth2_for_api/callback",
  method: 'get',
  params: {
    code: response.params.code,
    redirect_uri: redirectUrl
  }
})

// The result is from rails side.
const { auth_token, auth_email } = result.data;