NG4/2 - Export json data to CSV in Angular (in Front end) / component.ts

NG4/2 - Export json data to CSV in Angular in Front End / component.ts
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compose CSV from Component from JSON multi array and print data information one by one with 
corresponding header also one empty row Gap
Based on json response make the CSV file. Multi level json response object Iteration and Export to CSV
exportCSV_data.json
-------------------
{
"sections": {
"table1": [{
          "table1column1": "t1c1",
          "table1coloumn2": "t1c2"
          },
          {
          "table1column1": "t12c1",
          "table1coloumn2": "t12c2"
          }],
"table2": [{
        "table2column1": "t2c1",
        "table2column2": "t2c2",
        "table2column3": "t2c3",
        "table2column4": "t2c4"
       
        },
        {
        "table2column1": "t22c1",
        "table2column2": "t22c2",
        "table2column3": "t22c3",
        "table2column4": "t22c4"

         },
         {
          "table2column1": "t22c1",
          "table2column2": "t22c2",
          "table2column3": "t22c3",
          "table2column4": "t22c4"
         
          }],
"table3": [{
          "table3column1": "t3c1",
          "table3column2": "t3c2",
          "table3column3": "t3c3"
         
          },
          {
          "table3column1": "t32c1",
          "table3column2": "t32c2",
          "table3column3": "t33c3"
          }]
}
}


app.template.html
------------------

<div (click)="downloadCSVfromJSON()"> Download CSV file from JSON API response </div>


app.service.ts
---------------
import {Injectable} from '@angular/core';
import { Http, Response, Headers, RequestOptions } from '@angular/http';
import 'rxjs/add/operator/catch';
import { Observable } from 'rxjs/Observable';


@Injectable()
export class AppService {


  constructor( private http: Http) { }
  getJSONresponse(...agrs)Observable<any> {
let url =domainURL;
var argslength=args[0].length;
let itemName=args[0][argslength-2];
let itemId=args[0][argslength-1];
//return this.http.get(url+`${itemName}/${itemId}`)
return this.http.get(url+itemId)
.map(this.extractData)
.catch(this.handleError);
//.map(res => res.json());

}

 private extractData(res: Response) {
    let body = res.json();
    return body || { };
  }

   private handleError (error: any) {
    let errMsg = (error.message) ? error.message :
    error.status ? `${error.status} - ${error.statusText}` : 'Server error';
    console.error(errMsg); // log to console instead
    return Observable.throw(errMsg);
  }
}

app.component.ts
------------------
import { Component, NgModule, ViewContainerRef, ViewEncapsulation, ElementRef} from '@angular/core';
@component({
'selector':'app',
'styleUrls:['app.style.css'],
'templateUrl:['app.template.html']
})

export class Appcomponet {

JSON_API_Response:any;
url;  // router url 
constructor(private _servcie:appService){
this._servcie.getJSONresponse(this.url).subscribe( (data => any) =>{ 
if(data.success){
this.JSON_API_Response = data.JSONValue;
}else{
console.lgo('API Response Fail')
}
});
}

downloadCSVfromJSON(){
if(this.JSON_API_Response){
let jsonData = this.JSON_API_Response;

let Table1Key = ['table1column1', 'table1column2'];
let Table1Header = ['Table1 Column1', ' Table1 column 2'];
let Table1JSON = jsonData.section.table1;

let Table2Key = ['table2column1', 'table2column2','table2column3', 'table2column4'];
let Table1Header = ['Table1 Column1', ' Table1 column 2','Table2 column3', 'Table2 column4'];
let Table2JSON = jsonData.section.table2;

let Table3Key = ['table3column1', 'table3column2', 'table3column3'];
let Table3Header = ['Table3 Column1', ' Table3 column 2',, 'Table3 Column3'];
let Table3JSON = jsonData.section.table3;


let filteredData = this.getCSV(Table1Key,Table1Header,Table1JSON, Table2Key,Table2Header,Table2JSON, Table3Key,Table3Header,Table3JSON);
let ReportTitle = filename+ " " +level+" "+id;
let ShowLabel = true;
var arrData = typeof filteredData != 'object' ? JSON.parse(filteredData) : filteredData;
var CSV = '';
//below commnad retric first line of table 1 column 

// if (ShowLabel) {
//   var row = "";
//   for (let index=0;index<Table1Header.length;index++) {
//     row += Table1Header[index] + ',';
//   }
//   row = row.slice(0, -1);
//   CSV += row + '\r\n';
// }
for (var i = 0; i < arrData.length; i++) {
 var row = "";
 for (var index in arrData[i]) {
row += '"' + arrData[i][index] + '",';
 }
 row.slice(0, row.length - 1);
 CSV += row + '\r\n';
}

if (CSV == '') {
 console.log("Invalid data");
 return;
}
var fileName = ReportTitle.replace(/ /g, "_");
var uri = 'data:text/csv;charset=utf-8,' + encodeURI(CSV);
var link = document.createElement("a");
link.href = uri;
link.download = fileName + ".csv";
document.body.appendChild(link);
link.click();
document.body.removeChild(link);
 }
}

getCSV(Table1Key,Table1Header,Table1JSON, Table2Key,Table2Header,Table2JSON, Table3Key,Table3Header,Table3JSON){

let k=[];  let newlineItem = {}
              let title=['Table 1 Information '];
              k.push(title)
              k.push(Table1Header)
 for(let i=0;i<Table1JSON.length;i++){
 let item = {};
 for(let m=0;m<Table1Key.length;m++){
 item[Table1Key[m]]=Table1JSON[i][Table1Key[m]];
 }
 k.push(item);
 }
 
k.push(newlineItem); k.push(newlineItem)
title =['table 2 information in single line'];
k.push(title)
k.push(Table2Header)
for(let i=0;i<Table2JSON.length;i++){
 let item = {};
 for(let m=0;m<Table2Key.length;m++){
 item[Table2Key[m]]=Table2JSON[i][Table2Key[m]];
 }
 k.push(item);
 }
            
k.push(newlineItem); k.push(newlineItem)
title =['table 3 information in single line'];
k.push(title)
k.push(Table3Header)
for(let i=0;i<Table3JSON.length;i++){
 let item = {};
 for(let m=0;m<Table3Key.length;m++){
 item[Table3Key[m]]=Table3JSON[i][Table3Key[m]];
 }
 k.push(item);
 }
           
}

}
REf: https://stackoverflow.com/questions/8847766/how-to-convert-json-to-csv-format-and-store-in-a-variable