How to get param from url in angular 4?

Issue

I'm trying to get startdate from the URL. The URL looks like http://sitename/booking?startdate=28-08-2017

My code is below:

aap.module.ts

    import {...};

    @NgModule({
      declarations: [
        AppComponent, ModalComponent
      ],
      imports: [
        BrowserModule,
        FormsModule,
        HttpModule,
        JsonpModule,
        ReactiveFormsModule,
        RouterModule.forRoot([{
                path: '',
                component: AppComponent
            },
        ]),    
      ], 
      providers: [ContactService, AddonService, MainService],
      bootstrap: [AppComponent]
    })
    export class AppModule { }

aap.component.ts

import {...}
import {Router, ActivatedRoute, Params} from '@angular/router';

constructor(private activatedRoute: ActivatedRoute) {
  // subscribe to router event
  this.activatedRoute.queryParams.subscribe((params: Params) => {
    console.log(params);
  });

}

But its giving the below error

Unhandeled Promise rejection: No base href set. Please provide a value for the APP_BASE_HREF token or add a base element to the document. ; Zone: ; Task: Promise.then ; Value: Error: No base href set. Please provide a value for the APP_BASE_HREF token or add a base element to the document.

How does Angular know the base href?

Solution

This should do the trick retrieving the params from the url:

constructor(private activatedRoute: ActivatedRoute) {
  this.activatedRoute.queryParams.subscribe(params => {
        let date = params['startdate'];
        console.log(date); // Print the parameter to the console. 
    });
}

The local variable date should now contain the startdate parameter from the URL. The modules Router and Params can be removed (if not used somewhere else in the class).

Answered By - Ørjan