javascript - window is not defined angular universal third library

Question

I am working with the library ng2-mqtt and I used it im my component like this:

 import 'ng2-mqtt/mqttws31.js';
declare var Paho: any;

Now I am getting following error:

ReferenceError: window is not defined
    at Object.<anonymous> (/Users/Picchu/Documents/em3/node_modules/ng2-mqtt/mqttws31.js:2143:4)
    at Module._compile (module.js:556:32)
    at Object.Module._extensions..js (module.js:565:10)
    at Module.load (module.js:473:32)
    at tryModuleLoad (module.js:432:12)
    at Function.Module._load (module.js:424:3)
    at Module.require (module.js:483:17)
    at require (internal/module.js:20:19)
    at Object.<anonymous> (/Users/Picchu/Documents/em3/dist/server.js:18707:18)

How can I fix this issue?

Answer 1

One possible way to avoid server error is not to render the component(if it is an option) that uses window. Something like:

<ng-container *ngIf="isBrowser">
   <!-- mqttws31-component -->
   <mqttws31-component></mqttws31-component> 
</ng-container>

The isBrowser can be imported from(ng2)

import { isBrowser } from 'angular2-universal';

Or if ng4+, you can also define this in your browser module:

// app.browser
@NgModule({
  providers: [
    { provide: 'isBrowser', useValue: true }
  ]
})

then inject from constructor

export class SomeComponent implements OnInit {
  constructor(@Inject('isBrowser') private isBrowser: boolean)
  ngOnInit() { 
    // example usage, this could be anywhere in this Component of course
    if (this.isBrowser) { 
      alert('we're in the browser!');
    }
}