Q:

How to receive json array and iterate it in service file in Angular 4

I am working in an Angular4 application,In this I need to receive and iterate the json objects and pass it to another component. Here I have tried something please help me to solve this. 
json response format

service file. 
import { Injectable } from '@angular/core';
import { BehaviorSubject } from 'rxjs/BehaviorSubject';
import { HttpClient } from '@angular/common/http';
import 'rxjs/add/operator/map';

@Injectable()
export class CartdataService {

  public i_product_Path = new BehaviorSubject<any>('');
  i_cast_Product_Path = this.i_product_Path.asObservable();

  i_COUNTER :number;
  big_Image_Path:string[][];
 constructor(private http: HttpClient) { }

 get_Product_Path(pName: string) {
    this.current_product = pName.trim();
    this.http.get(`http://localhost:57036/api/data/GetImage/?imageName=${this.current_product}`)
    .subscribe((data) => {

        this.i_COUNTER = data[0].Count;
 if(this.i_COUNTER >0) {
          let i:number;
            for( i=0;i<=this.i_COUNTER;i++){
              this.big_Image_Path =data[0]['big_Images'];
            }
        }
 this.i_product_Path.next(this.big_Image_Path);
 });
  }
}

A:

Based on your input string this is working code, 
  parseJsonToObj() {
    const json = '[[{ "big_Images": "assets/Images/Product_Details_Page/Show1.png" }, { "big_Images": "assets/Images/Product_Details_Page/Show2.png" }, { "big_Images": "assets/Images/Product_Details_Page/Show3.png" }], [{ "small_Images": "assets/Images/Product_Details_Page/Product_Details_Page_Thumbnails/bal1.png" }, { "small_Images": "assets/Images/Product_Details_Page/Product_Details_Page_Thumbnails/bal2.png" }, { "small_Images": "assets/Images/Product_Details_Page/Product_Details_Page_Thumbnails/bal3.png" }], [{ "selected_Product_Image": "assets/Images/Modal_Screen/added.png" }]]'
    const images: Images = JSON.parse(json);
    console.log(images);
  }

To handle json created interfaces like below which can get your data easily,
export interface Images {
  big_Images: BImage[];
  small_Images: Simage[];
  selected_Product_Images: SelectedImage[]
}

export interface BImage {
  big_Images: string;
}

export interface Simage {
  small_Images: string;
}

export interface SelectedImage {
  selected_Product_Image: string;
}

Basically I am converting json response to typescript object. 

with given structure this should work for you 
  this.http.get(url).subscribe(
      (response: Images ) => {    
          console.log(response); 
      },
      error => {
          console.log(JSON.stringify(error));
      },
      () => { }
    );

