Global UI error handler

app.module.ts

import {BrowserModule} from '@angular/platform-browser';
import {ErrorHandler, NgModule, Injectable} from '@angular/core';
import {AppComponent} from './app.component';

@Injectable()
class UIErrorHandler extends ErrorHandler {
  constructor() {
    super();
  }
  handleError(error) {
    super.handleError(error);
    alert(`Error occurred:${error.message}`);
  }
}

@NgModule({
  declarations: [AppComponent],
  imports: [BrowserModule],
  // add the UI error handler
  providers: [
    provide: ErrorHandler,
    useClass: UIErrorHandler
  }],
  bootstrap: [AppComponent]
})

Line 20 { missing

should be
providers: [{