How I add Headers to http.get or http.post in Typescript and angular 2?

getHeroes (): Observable<Heros[]> {
    return this.http.get(this.heroesUrl)
      .map(this.extractData)
      .catch(this.handleError);
  }

Where I add the headers and how? looking for a simple example.

You can define a Headers object with a dictionary of HTTP key/value pairs, and then pass it in as an argument to http.get() and http.post() like this:

const headerDict = {
  'Content-Type': 'application/json',
  'Accept': 'application/json',
  'Access-Control-Allow-Headers': 'Content-Type',
}

const requestOptions = {                                                                                                                                                                                 
  headers: new Headers(headerDict), 
};

return this.http.get(this.heroesUrl, requestOptions)

Or, if it's a POST request:

const data = JSON.stringify(heroData);
return this.http.post(this.heroesUrl, data, requestOptions);

Since Angular 7 and up you have to use HttpHeaders class instead of Headers:

const requestOptions = {                                                                                                                                                                                 
  headers: new HttpHeaders(headerDict), 
};