parsing JSON into a Angular 2 object - json

Question

I am having the following issue.
I have a very large JSON string that has all the variables from the object.
object:
export class User {
ssn:string;
userId:string;
firstName:string;
lastName:string;
middleName:string;
office:string;
role:string;
lockCode:string;
command:string;
street:string;
city:string;
position:string;
zip:string;
phone:string;
dsn:string;
fax:string;
email:string;
pwEffectiveDate:any;
pwVaildationDate:any;
fromDate:any;
toDate:any;
systemAccess:string;
dmType:string;
accessInfoEffectiveDate:any;
accessInfoEffectiveTo:any;
availableOffices: string[];
availbleRole:string[];
}
JSON :
#Injectable()
export class SearchService {
getData() :any[] { return [
{"snn": "26999935-7", "userId": "EVD404", "firstName": "Chaney", "lastName": "Vernon", "middleName": "X", "office": "ADURT", "role": "GC", "lockCode": "Q", "command": "5th Grp", "street": "953-1348 Faucibus Rd.", "city": "Bienne-lez-Happart", "position": "Developer", "zip": "76222", "phone": "233-969-1834", "dsn": "359-887-4719", "fax": "157-376-6377", "email": "mauris.rhoncus#rhoncusDonec.com", "pwEffectiveDate": "13/03/17", "pwVaildationDate": "27/01/18", "fromDate": "10/11/17", "toDate": "21/12/17", "systemAccess": "GC", "dmType": "XJ", "accessInfoEffectiveDate": "26/12/2016", "accessInfoEffectiveTo": "06/06/2016", "availableOffices": "UUU", "availbleRole": "GC"},
{"snn": "43250813-7", "userId": "NSB626", "firstName": "Addison", "lastName": "Vernon", "middleName": "X", "office": "AUTRO", "role": "GC", "lockCode": "O", "command": "11th ACR", "street": "Ap #904-5416 Semper, Road", "city": "s Herenelderen", "position": "Developer", "zip": "26457", "phone": "890-600-3144", "dsn": "679-122-1054", "fax": "913-500-7495", "email": "Aenean#molestiesodales.com", "pwEffectiveDate": "11/06/17", "pwVaildationDate": "01/03/17", "fromDate": "05/08/17", "toDate": "29/09/16", "systemAccess": "LIMIT", "dmType": "NB", "accessInfoEffectiveDate": "19/04/2017", "accessInfoEffectiveTo": "13/04/2016", "availableOffices": "LLL", "availbleRole": "USER"},
Then I want to be able to call methods like below when I pass my service into the component:
getUserByLastName(lastName):User[]{
let temp: User[]=[];
for(let d of this.data) {
if(d.lastName == lastName){
temp.push(d);
}
}
return temp;
}
I have tried to JSON.parse but that did not work. I tried a few other things but none seem to stick.
---------------------------------Update 1----------------------------
It has been brought to my attention that I should be using an Observable. Here is what I have in trying to implement that but it is currently not working:
getUserBySSN():Observable<User[]> {
return this._http.get(this._url)
.map((response: Response) => response.json())
.do(data => console.log("User data" + JSON.stringify(data)))
.catch(this.handleError);
}
private handleError(error: Response) {
console.log(error);
return Observable.throw(error.json().error || 'Internal Server error');
}
I created a json file and set the variable url as its path. However I am getting to following error:
The type argument for type parameter 'T' cannot be inferred from the
usage. Consider specifying the type arguments explicitly. Type
argument candidate 'Response' is not a valid type argument because it
is not a supertype of candidate 'Response'. Types of property 'type'
are incompatible. Type 'string' is not assignable to type 'ResponseType'
It was suggested I use .map((response: Response) => <User[]> response.json()) but I was not allow to convert it.
After further research I found this is the the best approach and am trying to get it to function so later on I can use it to do actual HTTP calls against the DB.

Answer 1

In the world of Angular2, you should be using rxjs to achieve your requirement, as shown below
Your component should subscribe to the service values as below
this.userService.getUsers()
.filter(users =>{
for(let user of users) {
if(user.lastName == 'Vernon'){
this.users.push(user);
}}})
.subscribe(users => this.users = users,
error =>this.errorMessage =<any> error);
Your service should raise http calls and return data as below
import { Injectable } from '#angular/core';
import { Http, Response } from '#angular/http';
import { Observable } from 'rxjs/Observable';
import {User} from './user.model.ts';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/catch';
import 'rxjs/add/operator/do';
import 'rxjs/add/operator/filter';
#Injectable()
export class UserService {
private _url = "src/data.json";
constructor(private _http: Http) {
}
getUsers(): Observable<User[]> {
return this._http.get(this._url)
.map((response: Response) => <User[]>response.json())
.do(data => console.log("User data" + JSON.stringify(data)))
.catch(this.handleError);
}
private handleError(error: Response) {
console.log(error);
return Observable.throw(error.json().error || 'Internal Server error');
}
}
Also, you should not use Class for holding your data model, instead use interface as shown in the demo below.
LIVE DEMO