Singleton not keeping parity in node - node.js

Question

Having a very very peculiar issue happening:
When i start my node application, i set my access tokens to an instance of a model like so:
index.js
const token = new Tokens();
token.setTokens(access_token, refresh_token);
console.log(token.getTokens()) // WORKS
I then call the getter functions in my instance in different files.
RunSchedular.js
const tokens = Tokens.getInstance();
console.log('sched',tokens.getTokens()) //WORKS
API.js
export const POSTRequest = () => {
const currentTokens = Tokens.getInstance();
const refreshToken = currentTokens.getRefreshToken(); // DOES NOT WORK
const body = {
method: 'POST',
headers:
{
"Content-Type": "application/x-www-form-urlencoded",
"Cache-Control": "no-cache"
},
body: qs.stringify({
client_secret: clientSecret,
client_id: clientId,
refresh_token: refreshToken,
grant_type: 'refresh_token',
redirect_uri: redirectUri
})
};
return body;
}
My model is like so:
let instance = null;
export default class Tokens {
constructor() {
if(!instance) {
instance = this;
}
this.accessToken = '';
this.refreshToken = '';
}
getAccessToken() {
return this.accessToken;
}
setAccessToken(value) {
this.accessToken = value;
}
getRefreshToken() {
return this.refreshToken;
}
setRefreshToken(value) {
this.refreshToken = value;
}
getTokens() {
return {
accessToken: this.accessToken,
refreshToken: this.refreshToken
}
}
setTokens(accessToken,refreshToken) {
this.accessToken = accessToken;
this.refreshToken = refreshToken;
}
static getInstance() {
console.log('instance', instance)
if(!instance) {
instance = new Tokens();
}
return instance;
}
};
Any ideas why this could be happening? The instance in the API.js does not return my access tokens (access token = '' as per the constructor) where as the schedular.js and index.js returns my access token fine?
Is my Model not correct?

Answer 1

How are you importing the Tokens module? If the path is different, 2 different modules will be imported.
E.G.:
import { Tokens } from 'src/singletons/Tokens';
Will be a different object than:
import { Tokens } from './../singletons/Tokens';
More information about singletons in javascript.
More information about module caching in NodeJS.