JSON響應中的Angular 2過濾器

Question

我在從JSON響應中過濾數據時遇到問題。 我正在使用Google Geocoding API，並在我只想提取城市名稱的地方得到響應。 城市名稱存儲在數組之一的JSON響應中，其中types= "locality", "political"

在types=["locality", "political"]如何檢索城市名稱？

這是我的代碼：

geocoding.service.ts

 getLocation(lat: number, lon: number): Promise<any> {
    return this.http.get(this.apiUrl + lat + ',' + lon + '&key' + this.apiKey)
      .toPromise()
      .then((response) => Promise.resolve(response.json()));
  }

geocoding.ts

export class Geocoding {
    results: {
        address_components: {
            long_name: string;
            short_name: string;
        }
        formatted_address: string;
        types: {
            array: string;
            length: number;
        }
    }
    status: string;
}

weather.component.ts

import { Component, OnInit } from '@angular/core';
import { Observable } from 'rxjs/Observable';
import { GeocodingService } from '../data/google/geocoding/geocoding.service';
import { Geocoding } from '../data/google/geocoding/geocoding';

@Component({
  selector: 'app-weather',
  templateUrl: './weather.component.html',
  styleUrls: ['./weather.component.scss']
})

  location: Geocoding[];
  datasource: Geocoding[];
  sortedList: Geocoding[];

 ngOnInit() {
    this.findLocation2(52.406374, 16.9251681);
  }

 findLocation2(latitude: number, longtitude: number) {
    this.GeoService.getLocation(latitude, longtitude).then(data => {
      this.datasource = data;
      this.location = this.datasource;
      this.sortedList = this.location.filter(
        loc => loc.results.types.array === 'locality,political');
    });

當我運行時出現錯誤：

例外：未捕獲（承諾）：TypeError：_this.location.filter不是函數

Answer 1

我找到了解決方案！ @Ramesh Rajendran和@Sebastian都向我指出了正確的方向：

 findLocation(latitude: number, longtitude: number) {
    return this.GeoService.getData(latitude, longtitude).subscribe(g => {
      this.geo = g;
      this.GEOARRAY = g.results;
      if (isArray(this.GEOARRAY)) {
        this.location = this.GEOARRAY.filter(x => x.types[0] === "locality" && x.types[1] === "political");
      }
    });
  }

我創建了GEOARRAY並指向g.results （它是數組）。 然后我過濾了我想要的東西:)謝謝

Answer 2

this.location應該是一個數組。 因此，在執行filter之前，需要檢查this.location是否為數組。

findLocation2(latitude: number, longtitude: number) {
    this.GeoService.getLocation(latitude, longtitude).then(data => {
      this.datasource = data;
      this.location = this.datasource;
      if(Array.isArray(this.location)){
      this.sortedList = this.location.filter(
        loc => loc.results.types.array === 'locality,political');
    });
};