Add Contact To Campaign

addContact.ts

  public addContactToCampaign(contactResponse: any): Observable<any> {
    return this.getCampaignData()
                .pipe(
                  flatMap(response => {
                    this.campaign = response;
                    let contactsList = this.campaign.signup_list ? this.campaign.signup_list.map(l => l._id).join() + ',' + contactResponse.object._id  : contactResponse.object._id;
                    let objects = this.campaign.signup_list ? this.campaign.signup_list.push(contactResponse) : contactResponse;
                    let postBody = {
                      slug: this.campaign.slug,
                      metafields: [
                        {
                          type: 'objects',
                          key: 'signup_list',
                          title: 'Signup List',
                          value: contactsList
                        }
                      ],
                      write_key: config.writeKey
                    };
                    return this.http.patch(`${this.cosmicUrl}${this.bucketSlug}/edit-object-metafields`, postBody);
                  })
                );
  }