类型 'Promise<unknown>' 上不存在属性 'id'

Question

我的代码在将输入值发布到 json api 时遇到问题。请帮助我如何解决“Promise”类型上不存在属性“id”的问题。 抱歉，我只是这里的初学者。提前致谢。

//This is my code on component.ts
async OnNext() {
    let newCase = {PersonalInformation:{}, Status:"Pending", LastViewedPage:"personal-info", 
CreatedBy: this.User.userId}
    newCase.PersonalInformation = this.PersonalInformation.value
    const responseData = this.conn.CreateCase(newCase)
    if(responseData.id) {
      this.router.navigate(['address-info'])
    }else{
      this.errorDesc = "System error."
    }
  }

//This is my post code in my service definition.
  async CreateCase(data: any) {
    return new Promise((success, failed) => {
      this.http.post('http://localhost:3000/caseList', data).subscribe(
        data => {success(data)},
        error => {failed(error)}
      )
    })
  }