user1775718 user1775718 - 1 month ago 9x
React JSX Question

Scope with ES6 classes and module system

I'm having a problem due to scope/hoisting/load order. In the following the Auth0Lock is defined inside the

block on line 6, but not immediately outside of it, or within the class. Does anyone know why??

import { EventEmitter } from 'events';
import { isTokenExpired } from './jwtHelper';

const isClient = typeof window !== 'undefined';
if (isClient) {
let Auth0Lock = require('auth0-lock').default;
console.log('Auth0Lock inner', Auth0Lock);
console.log('Auth0Lock outer', Auth0Lock);
export default class AuthService extends EventEmitter {
constructor(clientId, domain) {
if (!isClient) {
return false;
// Configure Auth0
this.lock = new Auth0Lock(clientId, domain, {});
// Add callback for lock `authenticated` event
this.lock.on('authenticated', this._doAuthentication.bind(this));
// Add callback for lock `authorization_error` event
this.lock.on('authorization_error', this._authorizationError.bind(this));
// binds login functions to keep this context
this.login = this.login.bind(this);

// curtailed


The let keyword is block scoped:

let x = "hey";
{ let x= "hi"; }

The outer let x is not being overwritten because it is in it's own scope. To come back at your question. Your let Auth0Lock exists only in the if block.