Angular2：如何将每个对象迭代到可观察的包含对象数组数据？

Question

Hi guys i am just starting to learn(upgrade to be specific) Angular 2, i just have some few questions. how do i iterate each object in the observable of array object?

this is what i retrieve if i go get data from "api/v1/example" already postman on this and yes its working. .

// my arrayObject
[
{
    "userID": 12,
    "username": "admin1",
    "password": "admin2"
},
{
    "userID": 13,
    "username": "admin21",
    "password": "admin32"
},
{
    "userID": 14,
    "username": "admin221",
    "password": "admin72"
},
{
    "userID": 15,
    "username": "admin451",
    "password": "admin652"
},
{
    "userID": 16,
    "username": "admin561",
    "password": "admin1222"
},
{
    "userID": 17,
    "username": "admin154",
    "password": "admin572"
},
{
    "userID": 127,
    "username": "admin1254",
    "password": "admin5721"
}
]

So as what i said before i'm just learning angular 2, so i tried to use this dummy data to test observable, but somehow in my codes i can't really iterate each data in the object, this is what i tried so far

 myData: Any[];

 constructor(private _http: HttpClient) { }

 ngOnInit() {
     this._http.get<Any[]>("api/v1/example")
         .map(data => data["username"])
         .subscribe(data => console.log(data));
 }

but i don't get any data, i even tried the filter

filter(data => data["id"] > 0)

but still fails, but if i just subscribe immediately like this i can retrieve the data

 ngOnInit() {
     this._http.get<Any[]>("api/v1/example")
         .subscribe(data => console.log(data));
 }

i use the stream in java as reference for this but i think they don't work the same, thank you in advance guys

Answer 1

Try below code:

import { Observable } from 'rxjs/Observable';
import { from } from 'rxjs/observable/from';
import { of } from 'rxjs/observable/of';
import { map } from 'rxjs/operators';

    this._http.get<Any[]>("api/v1/example").pipe(
          map(d => { return d["username"]; })
        ).subscribe(data => console.log(data));

refer working stackblitz