服务器端number的Angular4 Typescript接口动态类型转换问题

Question

我有一个模型

export class School {
    school_id: number;
    school_name: string;
    school_code: string;
}

一旦我订阅了

我对学校数据的变量初始化

schools: School[] = [];

我的数据服务

getSchool(){
    return this.http.get(`${this.apiEndPoint}/api/getSchool`,this.jwt())
    .map((response:Response) => response.json() );
  }  

getSchoolData() {
    this.dataService.getSchool().subscribe(response => {
        this.schools = response.data;
        console.log(this.schools);
    });
  }

控制台日志对象提供了

[0:Object
school_code:"ALL"
school_id:"1"
school_name:"ALL"
]

我期望school_id是数字和它的设置字符串。我如何限制，使school_id将编号而不是接口。