How to use the class-transformer.serialize function in class-transformer

updateJob(job) {
    return this.http.put(this.getJobUrl(job.id), serialize(job), { headers: this.headers })
                    .toPromise()
                    .then(res => res.json())
                    .catch(this.handleError);
  }

addJob(job) {
    return this.http.post(this.url, serialize(job), { headers: this.headers })
                    .toPromise()
                    .then(res => res.json())
                    .catch(this.handleError);
  }

serialize (obj: T): string {
    return serialize(obj)
  }