Angular HttpParams object empty

Question

i'm working with angular version 11.2.1, and i'm trying to make an http request, a Get request with parameters and headers, the thing is, when i console.log them, they are empty, both of them, and the python is backend is throwing a 500 error.

this is the function in the service.ts

getOrigenes(): Observable<any>{ 
    
    const header = new HttpHeaders();
    header.set("Content-Type", "application/json");
    header.set("Authorization",  "Bearer md53b2b0eef781e8a6aaf7cf0565b780845");
    
    const params = new HttpParams();
    params.set('is_enum', '0');
    params.set('model', 'tc_interface_format');
    params.set('schema', 'acl_koncilia');

    const headersArrays = header.keys().map(x => ({ [x]: header.get(x) }));
    console.log(JSON.stringify(headersArrays));


    const paramsArray = params.keys().map(x => ({ [x]: params.get(x) }));
    console.log(JSON.stringify(paramsArray));
    
    return this.http.get('http://127.0.0.1:5000/read', {headers: header, params: params});

}

I'm not an Angular or TypeScript expert, so any help or advice would be appreciated.

Answer 1

HttpHeaders is an immutable structure, the set method does not add a key to the parameters, it creates a clone of the parameters with a new key inside, so you need to overwrite parameters with the result of the set method:

 params = params.set('is_enum', '0');

Details https://angular.io/api/common/http/HttpHeaders#set