How to get parameters from the Angular ActivatedRoute

angular parameters routing

11,139

Solution 1

Change to this.id = +params.get('id').

You should use the method get() because it returns a single value for the given parameter id. You were getting an error because params is not a key with id as a value.

export class RecipeEditComponent implements OnInit {
  id: number;
  editMode = false;

  constructor(private route: ActivatedRoute) { }

  ngOnInit() {
  // paramMap replaces params in Angular v4+
   this.route.paramMap.subscribe(params: ParamMap => {
        this.id = +params.get('id');
        console.log(this.id);     
  });
}

Solution 2

The problem was in the route definition: putting : instead of ::

Solution 3

I think the following code is going to work in your case:

ngOnInit() {
this.heroes$ = this.route.paramMap.pipe(
  switchMap(params => {
    // (+) before `params.get()` turns the string into a number
    this.selectedId = +params.get('id');
    return this.service.getHeroes();
  })
);

}

Also you can try this:

this.sessionId = this.route
  .queryParamMap
  .pipe(map(params => params.get('id') || 'None'));

11,139

Author by

faouzi Ch

Updated on June 05, 2022

Comments

faouzi Ch almost 2 years
I'm trying to get the prameter :id from my activated route using observables. When I print params on the console I get the right values for :id. But it's not the case for this.id. I get the value NaN. Can you tell me what is the problem
```
export class RecipeEditComponent implements OnInit {
  id: number;
  editMode = false;

  constructor(private route: ActivatedRoute) { }

  ngOnInit() {
    this.route.params.subscribe(
      (params: {id: string}) => {
        this.id = +params.id;
        console.log(this.id);
      }
    );
}
}
```
- penleychan about 5 years
  
  Could you put that code into your question as code block and not as image.
- robert about 5 years
  
  what you get if you console.log(params.id)?
- faouzi Ch about 5 years
  
  Undifined Even though I'm getting the right object when I print params the object with :id = 1
- robert about 5 years
  
  how do you call this route? what is in your browsers address bar?
- faouzi Ch about 5 years
  
  the route is : { path: '::id/edit', component: RecipeEditComponent} The link in the browser is: localhost:4200/recipes/0/edit
- robert about 5 years
  
  Is double colon :: a typo? Try with single one.
- faouzi Ch about 5 years
  
  @robert1 yes this was the problem thanks
faouzi Ch about 5 years

it shows this error: ERROR TypeError: "params.get is not a function"
Damien about 5 years

If you are using Angular v4+, change params to paramMap.
faouzi Ch about 5 years

I've changed it to paramMap but now it does print nothing on the console
Damien about 5 years

Do you have the console.log(this.id) in the code?
faouzi Ch about 5 years

Yes, now it prints 0 as value for 'this.id' But when I print params it gives me an object with the right values of 'id'
RadekF about 5 years

maybe try this: Number(params["id"])
Ellone almost 4 years

Why is there a + sign ? I haven't found anything on the documentation about it.
Damien almost 4 years

@Ellone The + sign changes the id from a string to a number.