If you use a TypeScript interface instead of a class, things are simpler:

Copyexport interface Employee {
    typeOfEmployee_id: number;
    department_id: number;
    permissions_id: number;
    maxWorkHours: number;
    employee_id: number;
    firstname: string;
    lastname: string;
    username: string;
    birthdate: Date;
    lastUpdate: Date;
}

let jsonObj = JSON.parse(employeeString); // string to "any" object first
let employee = jsonObj as Employee;

If you want a class, however, simple casting won't work. For example:

Copyclass Foo {
    name: string;
    public pump() { }
}

let jsonObj = JSON.parse('{ "name":"hello" }');
let fObj = jsonObj as Foo;
fObj.pump(); // crash, method is undefined!

For a class, you'll have to write a constructor which accepts a JSON string/object and then iterate through the properties to assign each member manually, like this:

Copyclass Foo {
    name: string;

    constructor(jsonStr: string) {
        let jsonObj = JSON.parse(jsonStr);
        for (let prop in jsonObj) {
            this[prop] = jsonObj[prop];
        }
    }
}

let fObj = new Foo(theJsonString);

you can use class-transformer which helps you to convert plain javascript objects to real es6 classes. With this real instances you can also use class methods.

import { Component, OnInit } from "@angular/core";
import ProductsJson from "./products.json";
import {plainToClass} from "class-transformer";

@Component({
  selector: "my-app",
  templateUrl: "./app.component.html",
  styleUrls: ["./app.component.css"]
})
export class AppComponent implements OnInit {
  productsJson: any = ProductsJson;
  products: Array<Product>;
  constructor() {}
  ngOnInit() {
    //this.products = <Product[]>this.productsJson;
    this.products = plainToClass(Product, this.productsJson as []);
    console.log(this.products);
  }
}
export class Product {
  id: number;
  name: string;
  description: string;
  relatedProducts: Array<number>;

  getId(){
    return this.id + "_ID";
  }
}

template:

<ul>
    <li *ngFor="let p of products">
        {{p.getId()}} {{p.id}} {{p.name}}
    </li>
</ul>

Just subscribe to your service method from your component as,

this.yourService.GetBlackListData().subscribe(result => this.result =result.rows);

and your Model should be as follows,

    export interface Column {
        table: string;
        name: string;
        datatype: string;
    }

    export interface Row {
        id: string;
        emailid: string;
        membershipid: string;
        phonenumber: string;
    }

    export interface BlacklistData {
        columns: Column[];
        rows: Row[];
    }

In your product.service.ts you are using stringify method in a wrong way..

Just use

JSON.stringify(product) 

instead of

JSON.stringify({product})

i have checked your problem and after this it's working absolutely fine.

As Abdul has pointed out you have a JSON array and you want a JSON object, there you need

  var eachProduct = 
                     {
                         "name": name,
                         "id": id,
                         "category":category,
                         "price":price
                     };

Now alert(eachProduct.name); will return name. And I assume by "How to pass the function parameters to the each product" you mean add an attribute to your JSON object. To do this you you would have

eachProduct["someAttribute"]='"value":someValue';

Try like this

View

<div ng-controller="MyCtrl">
    <div ng-repeat="user in _users" ng-init="myInfo=parJson(user.User.lastlogin)">
        <div ng-repeat="emp in myInfo.employees">{{emp.firstName}}</div>
    </div>
</div>

Controller

var myApp = angular.module('myApp', []);

function MyCtrl($scope) {
    $scope.getName = function (user) {
        return "Names";
    };

    $scope._users = [{
        "User": {
            "userid": "dummy",
                "lastlogin": "{\"employees\":[{\"firstName\":\"John\"},                   {\"firstName\":\"Blake\"}]}",
        }
    }];
    $scope.parJson = function (json) {
        return JSON.parse(json);
    }
    //console.log(JSON.parse($scope._users[0].User.lastlogin));
}

DEMO

you can also use angular.fromJson.

Like this

$scope.parJson = function (json) {
   return angular.fromJson(json);
}

DEMO