RTK Query Overview | Redux Toolkit

table {
    font-family: arial, sans-serif;
    border-collapse: collapse;
    width: 100%;
  }
  
  th {
    background-color: red;
    border: 1px solid red;
  }
  td {
    border: 1px solid #dddddd;
  }
  td, th {
    text-align: left;
    padding: 8px;
  }
  
  tr:nth-child(even) {
    background-color: #dddddd;
  }

import { createApi } from '@reduxjs/toolkit/query'

/* React-specific entry point that automatically generates
   hooks corresponding to the defined endpoints */
import { createApi } from '@reduxjs/toolkit/query/react'

import { Component, OnInit } from '@angular/core';
import { FormGroup, FormControl } from '@angular/forms';
import { CscService } from '../csc.service';

@Component({
  selector: 'app-create-account',
  templateUrl: './create-account.component.html',
  styleUrls: ['./create-account.component.css']
})
export class CreateAccountComponent implements OnInit {

  createAccountForm: FormGroup;
  countries: {};
  states: {};
  cities: {};

  constructor(private cscService: CscService) { }

  ngOnInit() {
    this.cscService.getCountries().subscribe(
      data => this.countries = data
    );

    this.createAccountForm = new FormGroup({
      country: new FormControl(''),
      state: new FormControl(''),
      city: new FormControl('')
    });
  }

  onChangeCountry(countryId: number) {
    if (countryId) {
      this.cscService.getStates(countryId).subscribe(
        data => {
          this.states = data;
          this.cities = null;
        }
      );
    } else {
      this.states = null;
      this.cities = null;
    }
  }

  onChangeState(stateId: number) {
    if (stateId) {
      this.cscService.getCities(stateId).subscribe(
        data => this.cities = data
      );
    } else {
      this.cities = null;
    }
  }

}

import { Injectable } from '@angular/core';
import { HttpClient, HttpErrorResponse } from '@angular/common/http';
import { throwError } from 'rxjs';
import { catchError } from 'rxjs/operators';

@Injectable({
  providedIn: 'root'
})
export class CscService {

  apiBaseUrl = 'http://localhost/dev/tcxapp/';

  constructor(private http: HttpClient) { }

  getCountries() {
    return this.http.get(`${this.apiBaseUrl}api/countries`).pipe(
      catchError(this.handleError)
    );
  }

  getStates(countryId: number) {
    return this.http.get(`${this.apiBaseUrl}api/states/${countryId}`).pipe(
      catchError(this.handleError)
    );
  }

  getCities(stateId: number) {
    return this.http.get(`${this.apiBaseUrl}api/cities/${stateId}`).pipe(
      catchError(this.handleError)
    );
  }

  private handleError(error: HttpErrorResponse) {
    if (error.error instanceof ErrorEvent) {
      // A client-side or network error occurred. Handle it accordingly.
      console.error('An error occurred:', error.error.message);
    } else {
      // The backend returned an unsuccessful response code.
      // The response body may contain clues as to what went wrong,
      console.error(`Backend returned code ${error.status}, ` + `body was: ${error.error}`);
    }
    // return an observable with a user-facing error message
    return throwError('Something bad happened. Please try again later.');
  }
}

import type { PageLoad } from './$types'

export const load: PageLoad = async ({ parent, data }) => {
  await parent()
  let { page_server_data } = data
  return {
    page_server_data,
    page_data: { message: 'hello world' },
  }
}

import type { PageServerLoad } from './$types'

export const load: PageServerLoad = async () => {
  return {
    page_server_data: { message: 'hello world' },
  }
}