HttpClient append parameter object to GET request - ionic-framework

Question

I'm quite the noob using Ionic or Angular for that matter. So as a cheat sheet I'm using the ionic-super-starter template (link below).
I am trying to make a get request to my API and it works just find if I'm doing it like this:
this.api.get('user/'+this.user.userId+'/entries?include=stuff&access_token=TOKEN');
but when I put the url params into an object it stops working:
let options = {
'include':'stuff',
'access_token':'TOKEN'
}
this.api.get('user/'+this.user.userId+'/entries', options);
The only error I get is "Unauthorized Request" since the options object including the access token was not appended to the url.
In the ionic-super-starter template the providers/api/api.ts calls .set() for each key in my params object:
if (params) {
reqOpts.params = new HttpParams();
for (let k in params) {
reqOpts.params.set(k, params[k]);
}
}
but according to Angular University this is not possible since "HTTPParams is immutable".
If it really was wrong to do this, I don't believe it would be in the ionic template. Nor would I believe that I would be the first person to come across this issue.
However, I am stuck here so any help would be appreciated.
Link to Angular University:
https://blog.angular-university.io/angular-http/#httprequestparameters
Link to ionic-super-starter:
https://github.com/ionic-team/starters/tree/master/ionic-angular/official/super

Answer 1

I think I figured it out myself:
if I write (in my src/providers/api/api.ts)
reqOpts.params = reqOpts.params.append(k, params[k]);
instead of
reqOpts.params.set(k, params[k]);
it works.
if you are using a loopback API as I am you might have nested objects like:
let options = {
"filter": {
"order": "date DESC"
},
"access_token":this.user._accessToken
};
this won’t work. try instead:
let options = {
"filter": '{"order":"date DESC"}',
"access_token":this.user._accessToken
};