如何获取来自“jsondata”的数据。在angular2中以所需的格式？

Question

数据输出是一个数组但需要输入'Month'，'data1%'之类的字符串， 分别在此.monthdata，this.data1data的'data2' 'data3'，0th position等。 this.monthdata的输出结果为

['Jan','feb']

必需输出

['Month','Jan','feb']    where 'Month' should come from jsondata.json

我在代码中提到过。

jsondata.json

[{
        "Month": "Jan",
        "data1%": "58.2",
        "data2": "90.38",
        "data3": "87.4",
        "data4": "80.85"
    },
    {
        "Month": "feb",
        "data1%": "57.2",
        "data2": "90.38",
        "data3": "57.4",
        "data4": "85.85"
    }
]

service.ts

gethpData(): Observable<any> {
    return this.http.get('assets/json/hfollder/jsondata.json')
      .map(this.extractData)
      .catch(this.handleError);
  }
  private extractData(res: Response) {
    const body = res.json();
    return body || [];
  }

  private handleError(error: any) {
    const errMsg = (error.message) ? error.message :
      error.status ? `${error.status} - ${error.statusText}` : 'Server error';
    console.error(errMsg);
    // alert('Server Error!');
    return Observable.throw(errMsg);
  }

test.component.html

<button id='btn1' (click)='getdata('btn1')'>btn1</button>
<button id='btn2' (click)='getdata('btn2')'>btn2</button>
<button id='btn3' (click)='getdata('btn3')'>btn3</button>
<button id='btn4' (click)='getdata('btn4')'>btn4</button>

test.component.ts

import { service } ....................// imported here
constructor(public jsonDataService: service){}

getdata = (id) => {
    this.jsonDataService.gethpData().subscribe(res => this.getPartOfData(id, res));
}

getPartOfData(id, res) {
    switch (id) {   
        case 'btn1':
//here getting data as ['','',''.......] where empty strings are data
//required data output as ['Month','','',''....]
            this.monthdata  = res.map(el => el.Month);
            break;          
        case 'btn2':
//here getting data as ['','',''.......] where empty strings are data
//required data output as ['data1%','','',''....]

            this.data1data  = res.map(el => el['data1%']);
            break;          
        case 'btn3':
//here getting data as ['','',''.......] where empty strings are data
//required data output as ['data2','','',''....]

            this.data2data  = res.map(el => data2: el.data2);
            break;          
    }
}

Answer 1

你可以这样做：

this.monthdata  = ['Month' , ...res.map(el => el.Month) ];

使用ES6的数组解构。 对其他人也一样。