GaramX

이 문서는 읽기 전용입니다. 원본을 볼 수는 있지만 바꿀 수는 없습니다. 문제가 있다고 생각하면 관리자에게 문의하세요.

===== HTTP and Observables =====

==== Observables ====
A sequence of items that arrive asynchronously over time.
HTTP call - single item
Single item - HTTP response

==== HTTP, Observables and RxJS ====
  - HTTP Get request from EmpService
  - Receive the observable and cast it into an employee array
  - Subscribe to the observable from EmpList and EmpDetail
  - Assign the employee array to a local variable

RxJS
  * Reactive Extensions from Javascript
  * External library to work with Obserables

<file javascript employee.service.ts>
import { Injectable } from '@angular/core';
import { HttpClient, HttpErrorResponse } from '@angular/common/http';
import { IEmployee } from './employee';
import { Observable } from 'rxjs';
import { catchError, retry } from 'rxjs/operators';

// @Injectable({
//   providedIn: 'root'
// })
@Injectable()
export class EmployeeService {
  private _url: string = "/assets/data/employees.json"

  constructor(private http: HttpClient) { }

  getEmployees(): Observable<IEmployee[]>{
    return this.http.get<IEmployee[]>(this._url)
      .pipe(
        catchError(this.errorHandler)
      );
  }
  errorHandler(error: HttpErrorResponse){
    return Observable.throw(error.message || "Server Error");
  }
}
</file>

GaramX

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