React Native project - cannot make API calls with AwsAmplify through custom library - react-native

Question

I have a react-native app (without expo) called myapp.
I have a private custom package called myapp-core, where I handle AwsAmplify services (Auth, Storage) - to do login/signOut/etc.
I want to use myapp-core in myapp project, so I added it as a dependency in package.json ("myapp-core": "file:../myapp-core",) and then yarn install.
The problem I’m facing is that when I call myapp-core.authService.login(username, password) from the mobile project, I catch the error:
“ { “line”:177826, “column”: 17, “sourceURL”:
“http://10.0.2.2:8081/index.delta?platform=android&dev=true&minify=false”
} ”
From my research, that means my custom library cannot make api calls - but I don’t know exactly.
When I use aws-amplify's Auth object directly in my mobile project, it works.
Hopefully relevant code:
/**=============================**/
/** myapp/CoreServices.js **/
import { AmplifyService } from “myapp-core";
export default class CoreServices {
constructor() {
AmplifyService.configure();
const auth = AmplifyService.authService();
auth
.login(“myusername”, “mypassword”)
.then(user => console.warn("success", user))
.catch(error => console.warn("error", error));
}
}
/**=============================**/
/** myapp-core/AmplifySevice.js **/
import Amplify from 'aws-amplify';
import AuthService from '../AuthService/AuthService';
import awsConfigs from '../aws-exports';
class AmplifyService {
static authServiceInstance = null;
static storageServiceInstance = null;
static configure(config = awsConfigs) {
if (config === null || config === undefined) {
throw new Error('AmplifyService must be initialized with Auth and Storage configurations.');
}
Amplify.configure({
Auth: { /*...*/ },
Storage: { /*...*/ }
});
}
static authService() {
if (!this.authServiceInstance) {
this.authServiceInstance = new AuthService();
}
return this.authServiceInstance;
}
static storageService() {
console.warn('storage service');
// initialize storage service
// return storage service
}
}

Answer 1

I managed to solve my project's issue.
Maybe someone will benefit from my solution.
The problem didn't have anything to do with AwsAmplify, but with the way I linked the projects: myapp-core with myapp.
The issue was that in the myapp-core I am using the aws-amplify package that I would normally link to the mobile projects (react-native link) but in my case I assumed (wrongly) that it wouldn't be the case.
The solution was to link whatever packages were needed in the iOS/Android projects to install the proper pods/gradle libraries, like react-native link amazon-cognito-identity-js for authentication.
... and now I am finally happy :))
Links that shed some light:
https://github.com/facebook/create-react-app/issues/1492
https://eshlox.net/2018/11/12/aws-amplify-react-native-typeerror-cannot-read-property-computemodpow-of-undefined/
In case somebody thinks this isn't the solution and I got lucky or something, please comment or post another response.