How can I get the user token from the context in a Sharepoint WebPart?

I have been working in a Sharepoint Webpart with TypeScript. I would like to obtain the user token to pass it as a parameter in the headers. How can I do this?.

So far, I have something like this:

public render(): void {
...
let request = this.getRequest(param1);
...
}

protected getRequest(param1: string): Promise<any> {

let loginURL = this.properties.url+"/admin/api/v2/list";

let body = '{"param":"'+param1+'"}';

let requestHeaders: Headers = new Headers(); requestHeaders.append("Accept-Tos", "true"); requestHeaders.append("Content-Type", "application/json"); requestHeaders.append("respondWithObject", "true");
**requestHeaders.append('Authorization', 'Bearer <TOKEN>'); ????**

let httpClientOptions: IHttpClientOptions = { body: body, headers: requestHeaders
};

return this.context.httpClient.post( loginURL,
HttpClient.configurations.v1, httpClientOptions)
.then((response: HttpClientResponse): any => {
return response.json();
});
}

Regards