Body of message not visible from promise returned

I have a post service that returns some data from service but I can’t access it in case of success. Here is the code

    return new Promise(resolve => {, JSON.stringify(body), {headers: headers})
             .subscribe(data => {
               console.log(data._body);   -------> This line gives error "Body doesn't exists"
               if(data.status == 200){
                resolve('You signed up successfully!');            
               } else {
                 resolve("Problem signing up! Please try again in a moment");
             error => {

Leading underscores indicate “don’t touch me”. Use methods such as text() and json() to access response bodies.